@Classic-Burger if it helps, I did some things with unit_actions.js here, including adding a cursor and sound queue. https://gitea.wildfiregames.com/0ad/0ad/pulls/7298/files

You'll need one for the game if this is implemented. It's free but not for commercial use.

Most of what you want to do is fairly simple (when understanding the structuring) in terms of modding and just requires you to make new templates and have entities be replaced on death by your new template. for example, - if a cav dies make it spawn a gaia horse - making a new gaia horse template and giving it the capturable component might work - if a structure is destroyed make it spawn an custom entity which holds treasure components so it can be gathered. - i think Wow has got quarries in his Delenda Est mod or something similar so you might take a peek there  templates are merged with their parents but children have priority when altering the same components. For example If a child states it has 500 capture points and it's parent has 5000, the capture points will be 500 when they are merged.

just wondering if you know that 0AD has the loot system already working in the main game.

actually, 0ad has docks. You should look how those work and if their behavior can be replicated. In general, I would think most if not all of these mechanics would require adding JS components to the game or at least editing them. What we have is less flexible than you may think. Also, adding buttons is no joke either. Unfortunately, it's a completely independent programming task. I whish we had better tutorials for this stuff, honestly I couldn't even start by creating a new dummy component without asking here for a reproducible example.

@Classic-Burger, just did. Thanks.

Sorry for late reply, overlooked your reply $ apt show libsdl2 N: Paket libsdl2 kann nicht gefunden werden. N: Paket libsdl2 kann nicht gefunden werden. E: Keine Pakete gefunden Maybe I can fix it by trying to install libsdl2 ?  Or can this make things worse?