Why package.json has disappeared?

Trying to deploy GitHub - vporton/socialism: AI Internet Socialism - AI paying salaries to scientists and free software devs by just giving it the repo URL - Why doesn’t it see the package.json in a subdirectory?

#12 4.829 npm error enoent Could not read package.json: Error: ENOENT: no such file or directory, open '/app/backend/package.json'

It does a weird thing: Instead of copying the entire directory, it copies just two files. No idea, why.

#11 [build 2/6] COPY package-lock.json package.json ./