FEXRootFSFetcher does not work in a docker image build step.
Currently, I am unable to run `yes 1 | FEXRootFSFetcher` within a docker build step, as the output is not a TTY. In such a case, the tool attempts to open a graphical interface and fails to run.

A possible fix would be introducing an environment variable or argument to the program to force it to run in terminal mode.