In-app user manual
The GUI should be as intuitive as possible so that no user manual is necessary. However, in cases such as backend usage and integration, some textual guidance may be welcome.
Proposal: Include small buttons or links in strategic locations, so that a contextual text box would optionally open on hovering the button, with limited info, and clicking the button would open a new tab and load a related documentation page.
This task also includes writing such a documentation.