Improve iconography usability by adding a legend

Removing from Postponed as the dependency has been committed.

I'm not going to lie the addition of a legend doesn't feel as helpful as a tooltip (title text) on the icon on the card. I know this is being discussed. https://www.drupal.org/project/project_browser/issues/3293909 🐛 Security and maintained icons require alt text, should not use title attribute Active however, my feeling from a user standpoint is that a legend could easily be ignored or not helpful because it's not on the card itself and viewable all the time.

I disagree that a legend isn't helpful. Accessibility guidelines suggest that icons should be accompanied by visible text descriptions wherever feasible, and tooltips are generally not an option when a user isn't using a pointer device. This makes the alt-vs-title attribute issue 🐛 Security and maintained icons require alt text, should not use title attribute Active less of a problem because visible text should always be read by screen readers, and it makes icon descriptions available when not using pointer devices. While it'd take some rearranging, I think it'd be more than feasible to include brief text descriptions in the cards. It could even be something like "Covered" and "Maintained" with a more verbose description in the detail view (which is effectively what we're doing already).

More broadly, I feel especially for people new to Drupal that we'd rather make this information readily visible instead of making them go out of their way find out what it means. I feel like "hover over something for a tooltip describing it" is no longer something we can count on people to know to do — if it's even possible on their device.

I'm of the opinion that having a title and alt tag for an icon is more than enough. Adding a legend just clutters the display.

If we wanted to have easily visible text a hover effect where hovering over an icon would reveal text could be an option, but I feel that for now an alt and title are more than enough.