I have granted Firefox Reality storage permission. I transferred my files with Sidequest to sdcard/myfolder/index.html

Any ideas?

When you select the file to open in the file manager app on that device, are you given a choice of apps to use to open it? Can you choose Firefox Reality?

Thank you for your help. But there ist no file manager app on the Oculus Quest... :-(

If I enter any Link in the adress field, it is opened as a Google Search. I also tried to set the Link that I want to open as the Starting Page, but that didn't work either. Seems like Firefox Reality can not open local files. Too bad!