You can add an icon to be displayed in in-game addon lists (like the addon enable/disable dialog and the addon compartment menu) by adding something like this to your toc file:

## IconTexture: Interface\Icons\sanctum_features_missiontable

You can invoke /xpbar from the compartment menu (just under the calendar button at top right of the in-game UI) with something like this toc entry:

## AddonCompartmentFunc: mslc_OnAddonCompartmentClick

(Examples are from https://github.com/SpareSimian/MissingShadowlandsCompanions)

https://warcraft.wiki.gg/wiki/Addon_compartment
https://www.reddit.com/r/wow/comments/13a7hwf/addon_developers_please_start_using_the_new/

I know about the mentioned features. Just need time to implement them