Experimental features: string cleanup, use variable

In one of the recent MRs for string cleanup #7598 (closed) we created a new variable for the long-form Experiment text. We should implement that variable in the output of all the commands that need it, and make sure all our experimental items are clearly marked.

I'm separating out this work from #7598 (closed) because I'll probably need a bit of FE help.

Related items

• Related to Track holistic UI string cleanup (#7598 - closed)
• Related to !1564 (comment 1980930062) where it came up in an outside contributor's MR.