When I get time, this'll maybe be a proper mod manager. For now, it's a helper program to let me
install mods reversibly, by mounting the Data directory as the lower layer of an
OverlayFS, and creating a
loop device for mods.
Since mount requires root, the nvlmm executable must be run with sudo, or have the
CAP_SYS_ADMIN capability (sadly, no specific capability exists for managing mounts...) added via:
setcap cap_sys_admin+ep /path/to/nvlmm
Run nvlmm help for usage information.