Maybe a extension that can do these things ?

[Mickmick21]

The things the extension could do is : delete sprites, add / remove variables, add / remove lists, remove sounds, and remove costumes. I have seen an extension to delete sprites, but it's very buggy and in a fork (not a URL)

[softedco]

The things the extension could do is : delete sprites, add / remove variables, add / remove lists, remove sounds, and remove costumes. I have seen an extension to delete sprites, but it's very buggy and in a fork (not a URL)

I get adding/removing variables/lists but why would you need the rest?

[Mickmick21]

delete sprites cuz ShovelUtilis can IMPORT them from a URL (or data uri), but what of getting rid of the imported sprite ?

[Mickmick21]

same for the others

[Flappy25]

The things the extension could do is : delete sprites, add / remove variables, add / remove lists, remove sounds, and remove costumes. I have seen an extension to delete sprites, but it's very buggy and in a fork (not a URL)

I don't think this would help much because you don't need to delete assets from the editor. Just hide them or make them stop working.