I do have git repository with 2 remotes.
.git/config looks like

[remote "primary"]
    url = ssh://[email protected]/projectname/android.git
    fetch = +refs/heads/*:refs/remotes/primary/*
[branch "develop"]
    remote = primary
    merge = refs/heads/develop
[remote "secondary"]
    url = [email protected]:projectname/android.git
    fetch = +refs/heads/*:refs/remotes//*
[remote "origin"]
    url = ssh://[email protected]/projectname/android.git
    fetch = +refs/heads/*:refs/remotes/origin/*
    pushurl = ssh://[email protected]/projectname/android.git
    pushurl = [email protected]:projectname/android.git

git.secondary.com is local Forgejo(gitea fork) instance. I have admin access to it.
git.primary.com is corporate repo. I only have write access to branches and need to follow some rules

I need repository on git.secondary.com to have several additional files in specifc subolder (.forgejo/) which shouldn’t be pushed to git.primary.com.
I need this to automate running of tests and perform some automated analytics

How I can do that?