project tags should be usable in search

Yes, useful. :)

In large organizations and governments it is extremely beneficial to tag a project with things like: owner-group-1, legacy, dotnet Project tags should be usable from the API as well, perhaps provide a way to search for projects by tag, as well as edit and apply tags by the API.

Any plans to implement this feature?

It's be useful for our company too.

Many thanks

It now requires a lot of clicks to explore the tags:

Projects -> Explore projects -> All -> Tags dropdown.

Trying this on GitLab.com also shows how limited their usability is in the current version since the list contains almost 5000 tags, and would only be useful if searchable.

In addition to making tags searchable, I would love to see tags expanded with e.g.:

Project Settings: Same UI for adding tags as used with labels: When the user starts typing a tag, a dropdown filters through existing tags of all accessible projects, necessary to avoid lots of almost identical tags such as "gitlab ci" and "gitlab CI".
Project view "Trending tags" or "Tag cloud".

In the meantime it seems that the project description is searchable, and adding tags there will do the job in a basic way.