Nextcloud app not able to view/edit *.tex

I realized that the Nextcloud iOS app is unable to open *.tex files even if its defined as text in resources/config/mimetypealiases.dist.json. Instead you are presented with a file share dialogue.

Does the app ignore the mime-type set by the server? Is it possible to add that the app respect the server mime-type or at least add *.tex to the list of editable text files?