Glyphs beta (1005) cannot import some OTF or TTF files, e.g. the FiraSans 4.203 Fonts from https://github.com/carrois/Fira. Version 2.4.1 (983) can open them.
Beta shows an alertbox with text:
Das Dokument „FiraSans-Regular.otf“ konnte nicht geöffnet werden. Error while reading the document: /path/to/Fira-4_2/Fira_Sans_4_2/FiraSans_OTF_4203/Normal/FiraSans-Regular.otf
(-[OTPairPos setFont:]: unrecognized selector sent to instance 0x6000002f3900)
After opening and reexporting the file with Fontlab, Glyphs beta can open the file…