With the extensive help text at the top of the page, the modules listing at the left, the roles multi-select box, and the "Display permissions that are" section, you are likely to only be able to see one or two permissions—or less—without scrolling, which reduces the fast feedback that FPA could provide. See screenshot below.
The "Display permissions that are" section includes the below text (twice, but that's another issue).
Applies to all visible roles.
Unsaved changes are not counted.
Most effective when a single role is visible.
Empty module rows sometimes display when used with permission filter.
Enable module and visit permissions page with Claro theme while viewing with a standard laptop screen.
Add a configuration page with an option for a simple mode that removes help text, modules listing, roles multi-select box, and "Display permissions that are" section (or option to remove each individually) OR a toggle on the permissions page to "Show advanced filters & help" / "Hide advanced filters & help" with (in my ideal world) them hidden by default.
See if this change is wanted and will be accepted.
Pick the direction.
Implement the configuration and/or toggle.
The above described ones.
Active
4.0
Documentation
Turns out the module i want for this is https://www.drupal.org/project/permissions_filter →
Could we update the project page to list it as an alternative?
And this simple filter functionality is now in Drupal core! Woohoo!