ParseError: syntax error, unexpected ‘)’, expecting variable (T_VARIABLE) in Composer\Autoload\includeFile() (line 102 of /app/web/modules/contrib/single_content_sync/src/Plugin/SingleContentSyncFieldProcessor/FileAsset.php)

Here is the patch

what's your php version?

I see, the module still supports php 7.4, and that syntax is available in php 8

I will create a separate issue to drop php 7 support in 2.x