As part of updates to the older file-system drivers for Linux 6.6, the ReiserFS file-system is no longer marked as “Supported” but is officially treated as “Obsolete” within the Linux kernel.
The linux-fs merge for the Linux 6.6 cycle now treats ReiserFS as obsolete, the file-system long ago used by default on the likes of SUSE Linux.
Last year with Linux 5.18 ReiserFS was deprecated and now with it being obsolete, it will likely be dropped from the mainline Linux kernel within the next two to three years. Last year openSUSE Tumbleweed also ended ReiserFS support as one of the few distributions supporting it as an option.
The story of ReiserFS is a sad one – its creator, Hans Reiser, was charged with and convicted of the murder of his wife. The successor to ReiserFS, Reiser5, is still seeing sporadic development, but most likely won’t be mainlined any time soon.