This is call for help from all you experienced modders out here.
I'm currently developing a race mod (soon to be announced if all goes well), and I'm using the necron "teleport to building" feature (squad_jump_ext with teleport=true and teleport_summon=true)
The thing is, I want to change the way the button looks (not playing necrons, so that doesn't fit).
I first tried with the texture field available in the rgd, but that doesn't seem to work. Same way with title and description.
Editing taskbar.lua (within the frame of FreeUI), on the other hand, seems to work for both title and description, which is nice. The way it works is it binds a modal button and gives it different tooltips depending on what kind of "jump" the unit has. Editing the UCS pointer for teleport_summon does the trick.
As for the texture, there is also a field in there, but it does nothing when changed. My guess is the game pulls it out of somewhere else depending on the modality of the button (jump type), but I haven't been able to find it.
I know this is rather speciffic, but I refuse to believe it's hardcoded.