Avoid PHP warning in fopen, fixes #6296
Avoid PHP warning in fopen, fixes #6296

artefactual/atom,kyfr59/atom-cg35,artefactual/atom,artefactual/binder,artefactual/atom,Surfrdan/atom,artefactual/binder,CENDARI/atom,kyfr59/atom-cg35,artefactual/binder,Surfrdan/atom,artefactual/binder,Surfrdan/atom,kyfr59/atom-cg35,CENDARI/atom,CENDARI/atom