To clarify I'm not asking for btrfs to be supported by GL. What I am asking for is a Linux kernel 5.5+ for (in my case Slate AX if not others) & the accompanying kmod-fs-btrfs & btrfs-progs + related dependencies to be added to the GL repos. The intent is to have access to a fully modern file system available to install to use on an attached SSD/NVME via USB as would be expected by running a current stable release of OWRT 23.05.x. I would not expect such an advanced file system to be on the device OOTB.
As I've said here, elsewhere, the stale kernels & outdated repos GL builds on is very much a limiting factor to these devices. Eg: OWRT 23.05.6 is the last release of the 23.05 series but GL is still building on 23.05-SNAPSHOT — not even a stable 23.05.0 which was released 2023 October. OWRT's 23.05 series is fully EOL as of 2025 August.
GL.iNet needs to close the gap between whatever they're releasing & Upstream's releases. A window of one or two services releases behind is one thing but whole version numbers and near two (2) years out of date isn't doing the credibility of a ODM in business some 15 years any favors.
Pass that along to your PMs, please, if I haven't asked already.