On my Drupal 9.5 Beta2 installation running on PHP 8.1.11 when I enable bootstrap_styles and have it configured to have the module provide aos I am getting the following and animation does not work:
Warning: Undefined array key 1 in Drupal\Core\Asset\LibraryDependencyResolver->doGetDependencies() (line 67 of core/lib/Drupal/Core/Asset/LibraryDependencyResolver.php).
Drupal\Core\Asset\LibraryDependencyResolver->doGetDependencies(Array, Array) (Line: 73)
Drupal\Core\Asset\LibraryDependencyResolver->doGetDependencies(Array) (Line: 41)
Drupal\Core\Asset\LibraryDependencyResolver->getLibrariesWithDependencies(Array) (Line: 104)
Drupal\Core\Asset\AssetResolver->getLibrariesToLoad(Object) (Line: 116)
Drupal\Core\Asset\AssetResolver->getCssAssets(Object, ) (Line: 324)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAssetLibraries(Object, Array) (Line: 158)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAttachments(Object) (Line: 94)
Drupal\big_pipe\Render\BigPipeResponseAttachmentsProcessor->processAttachments(Object) (Line: 45)
Drupal\Core\EventSubscriber\HtmlResponseSubscriber->onRespond(Object, 'kernel.response', Object)
call_user_func(Array, Object, 'kernel.response', Object) (Line: 142)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object, 'kernel.response') (Line: 192)
Symfony\Component\HttpKernel\HttpKernel->filterResponse(Object, Object, 1) (Line: 180)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 81)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 58)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 707)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)
User warning: The following theme is missing from the file system: aos.local in Drupal\Core\Extension\ExtensionPathResolver->getPathname() (line 63 of core/lib/Drupal/Core/Extension/ExtensionPathResolver.php).
Drupal\Core\Extension\ExtensionPathResolver->getPathname('theme', 'aos.local') (Line: 85)
Drupal\Core\Extension\ExtensionPathResolver->getPath('theme', 'aos.local') (Line: 123)
Drupal\Core\Asset\LibraryDiscoveryParser->buildByExtension('aos.local') (Line: 87)
Drupal\Core\Asset\LibraryDiscoveryCollector->getLibraryDefinitions('aos.local') (Line: 66)
Drupal\Core\Asset\LibraryDiscoveryCollector->resolveCacheMiss('aos.local') (Line: 149)
Drupal\Core\Cache\CacheCollector->get('aos.local') (Line: 44)
Drupal\Core\Asset\LibraryDiscovery->getLibrariesByExtension('aos.local') (Line: 58)
Drupal\Core\Asset\LibraryDiscovery->getLibraryByName('aos.local', NULL) (Line: 71)
Drupal\Core\Asset\LibraryDependencyResolver->doGetDependencies(Array, Array) (Line: 73)
Drupal\Core\Asset\LibraryDependencyResolver->doGetDependencies(Array) (Line: 41)
Drupal\Core\Asset\LibraryDependencyResolver->getLibrariesWithDependencies(Array) (Line: 104)
Drupal\Core\Asset\AssetResolver->getLibrariesToLoad(Object) (Line: 116)
Drupal\Core\Asset\AssetResolver->getCssAssets(Object, ) (Line: 324)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAssetLibraries(Object, Array) (Line: 158)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAttachments(Object) (Line: 94)
Drupal\big_pipe\Render\BigPipeResponseAttachmentsProcessor->processAttachments(Object) (Line: 45)
Drupal\Core\EventSubscriber\HtmlResponseSubscriber->onRespond(Object, 'kernel.response', Object)
call_user_func(Array, Object, 'kernel.response', Object) (Line: 142)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object, 'kernel.response') (Line: 192)
Symfony\Component\HttpKernel\HttpKernel->filterResponse(Object, Object, 1) (Line: 180)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 81)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 58)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 707)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)
Deprecated function: dirname(): Passing null to parameter #1 ($path) of type string is deprecated in Drupal\Core\Extension\ExtensionPathResolver->getPath() (line 85 of core/lib/Drupal/Core/Extension/ExtensionPathResolver.php).
Drupal\Core\Extension\ExtensionPathResolver->getPath('theme', 'aos.local') (Line: 123)
Drupal\Core\Asset\LibraryDiscoveryParser->buildByExtension('aos.local') (Line: 87)
Drupal\Core\Asset\LibraryDiscoveryCollector->getLibraryDefinitions('aos.local') (Line: 66)
Drupal\Core\Asset\LibraryDiscoveryCollector->resolveCacheMiss('aos.local') (Line: 149)
Drupal\Core\Cache\CacheCollector->get('aos.local') (Line: 44)
Drupal\Core\Asset\LibraryDiscovery->getLibrariesByExtension('aos.local') (Line: 58)
Drupal\Core\Asset\LibraryDiscovery->getLibraryByName('aos.local', NULL) (Line: 71)
Drupal\Core\Asset\LibraryDependencyResolver->doGetDependencies(Array, Array) (Line: 73)
Drupal\Core\Asset\LibraryDependencyResolver->doGetDependencies(Array) (Line: 41)
Drupal\Core\Asset\LibraryDependencyResolver->getLibrariesWithDependencies(Array) (Line: 104)
Drupal\Core\Asset\AssetResolver->getLibrariesToLoad(Object) (Line: 116)
Drupal\Core\Asset\AssetResolver->getCssAssets(Object, ) (Line: 324)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAssetLibraries(Object, Array) (Line: 158)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAttachments(Object) (Line: 94)
Drupal\big_pipe\Render\BigPipeResponseAttachmentsProcessor->processAttachments(Object) (Line: 45)
Drupal\Core\EventSubscriber\HtmlResponseSubscriber->onRespond(Object, 'kernel.response', Object)
call_user_func(Array, Object, 'kernel.response', Object) (Line: 142)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object, 'kernel.response') (Line: 192)
Symfony\Component\HttpKernel\HttpKernel->filterResponse(Object, Object, 1) (Line: 180)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 81)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 58)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 707)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)
Warning: Undefined array key 1 in Drupal\Core\Asset\AssetResolver->getCssAssets() (line 133 of core/lib/Drupal/Core/Asset/AssetResolver.php).
Drupal\Core\Asset\AssetResolver->getCssAssets(Object, ) (Line: 324)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAssetLibraries(Object, Array) (Line: 158)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAttachments(Object) (Line: 94)
Drupal\big_pipe\Render\BigPipeResponseAttachmentsProcessor->processAttachments(Object) (Line: 45)
Drupal\Core\EventSubscriber\HtmlResponseSubscriber->onRespond(Object, 'kernel.response', Object)
call_user_func(Array, Object, 'kernel.response', Object) (Line: 142)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object, 'kernel.response') (Line: 192)
Symfony\Component\HttpKernel\HttpKernel->filterResponse(Object, Object, 1) (Line: 180)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 81)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 58)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 707)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)
Warning: Undefined array key 1 in Drupal\Core\Asset\AssetResolver->getJsAssets() (line 239 of core/lib/Drupal/Core/Asset/AssetResolver.php).
Drupal\Core\Asset\AssetResolver->getJsAssets(Object, ) (Line: 331)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAssetLibraries(Object, Array) (Line: 158)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAttachments(Object) (Line: 94)
Drupal\big_pipe\Render\BigPipeResponseAttachmentsProcessor->processAttachments(Object) (Line: 45)
Drupal\Core\EventSubscriber\HtmlResponseSubscriber->onRespond(Object, 'kernel.response', Object)
call_user_func(Array, Object, 'kernel.response', Object) (Line: 142)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object, 'kernel.response') (Line: 192)
Symfony\Component\HttpKernel\HttpKernel->filterResponse(Object, Object, 1) (Line: 180)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 81)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 58)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 707)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)
Warning: Undefined array key 1 in Drupal\Core\Asset\AssetResolver->getJsAssets() (line 251 of core/lib/Drupal/Core/Asset/AssetResolver.php).
Drupal\Core\Asset\AssetResolver->getJsAssets(Object, ) (Line: 331)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAssetLibraries(Object, Array) (Line: 158)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAttachments(Object) (Line: 94)
Drupal\big_pipe\Render\BigPipeResponseAttachmentsProcessor->processAttachments(Object) (Line: 45)
Drupal\Core\EventSubscriber\HtmlResponseSubscriber->onRespond(Object, 'kernel.response', Object)
call_user_func(Array, Object, 'kernel.response', Object) (Line: 142)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object, 'kernel.response') (Line: 192)
Symfony\Component\HttpKernel\HttpKernel->filterResponse(Object, Object, 1) (Line: 180)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 81)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 58)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 707)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)
Warning: Undefined array key 1 in Drupal\Core\Asset\AssetResolver->getJsSettingsAssets() (line 199 of core/lib/Drupal/Core/Asset/AssetResolver.php).
Drupal\Core\Asset\AssetResolver->getJsSettingsAssets(Object) (Line: 313)
Drupal\Core\Asset\AssetResolver->getJsAssets(Object, ) (Line: 331)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAssetLibraries(Object, Array) (Line: 158)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAttachments(Object) (Line: 94)
Drupal\big_pipe\Render\BigPipeResponseAttachmentsProcessor->processAttachments(Object) (Line: 45)
Drupal\Core\EventSubscriber\HtmlResponseSubscriber->onRespond(Object, 'kernel.response', Object)
call_user_func(Array, Object, 'kernel.response', Object) (Line: 142)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object, 'kernel.response') (Line: 192)
Symfony\Component\HttpKernel\HttpKernel->filterResponse(Object, Object, 1) (Line: 180)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 81)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 58)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 707)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)