Accessibility is a default official app that is not even listed on this help forum’s categories, nor in the official documentation as far as I can tell. “File a Bug” takes me to the Nextcloud Server page.
Accessibility enhance the usage and display of nextcloud…
Universal access is very important to us. We follow web standards and check to make everything usable also without mouse, and assistive software such as screenreaders.
We aim to be compliant with the {guidelines} 2.1 on AA level,
with the high contrast theme even on AAA level.
Accessibility provide keyboard navigation, some font options, add highcontrast style for dark mode, and may-add/provide other related features.
Seems to be removed in NC v25 by the way. Could not find any source for that but maybe it is just not needed anymore.
Actually accessibility has been greatly expanded. It is built into your user settings experience.
So it’s part of core now, therefore no dedicated app needed anymore.