btrfs-progs/Documentation/Experimental.md

Experimental features

Experimental or unstable features may be enabled by

./configure --enable-experimental

but as it says, the interface, command names, output formatting should be considered unstable and not for production use. However testing is welcome and feedback or bugs filed as issues.

In the code use it like:

if (EXPERIMENTAL) {
    ...
}

in case it does not interfere with other code or does not depend on an #ifdef where it would break default build.

Or:

#if EXPERIMENTAL
...
#endif

for larger code blocks.

Each feature should be tracked in an issue with label experimental, with a description and a todo list items. Individual tasks can be tracked in other issues if needed.