I agree there shouldn't be, and it would be fairly easy to check in the json file that it actually does what it "should" do in the build and nothing else, but have you ever actually checked? The only time I've ever even looked was when I wanted to change a build option for some reason, and that's not often.
And then the frequent use of git submodules makes it even worse: that's often a whole lot of code that even the author of the flatpak doesn't have control over.
Hm. You're right. I haven't. And I guess the entire problem is that we shouldn't just assume somebody else has.
The JSON manifest is a much smaller attack surface than uploading random binaries would be though. And the standardized build procedure should make it relatively easy to tell if something's out of the ordinary and should be raising eyebrows, or even automate much of it.
Maybe stick an `alias CheckFlatHub=` for a LLM prompt, or just some plain regexes, in `.bashrc`? Looking for fishing URLs and install commands sounds like a relatively simple problem, as far as security challenges go.
And then the frequent use of git submodules makes it even worse: that's often a whole lot of code that even the author of the flatpak doesn't have control over.