title: Why is git creating read-only (444) files?
body: <p>Using a shared repo (core.sharedRepository=group) we ran into some issues with git creating read-only (permissions 444) files. No matter which git config items I twiddle there always seems to be some read-only meta-data created on the server side when we push. These files are in .git/ (or objects/ in a bare repo).</p>
  
  <p>Do you really never need to write to these files again (regardless of what git operations you perform)? They may be representative of commit deltas, so really should not be changed, but I was hoping someone could clarify this.</p>
  
  <p>For the inquisitive, the relevant lines look to be 856 and 867 of builtin/index-pack.c in git.</p>