ScratchMark sounds great. For an icon, why not an actual scratch mark across a few pages? You know, the typical 3 ripped scratches, maybe with a sneaky paw print in the corner of the pages.

It pretty much does, at least for all the apps I want to use I have no need to use fdroid. If not, maintainers should probably publish apks and have reproducible builds

Obtanium is also a good alternative btw

Let’s encrypt brother