The package isn't meant for end-users, it's for developers of ladybird to ensure that all development dependencies are satisfied (building repeatedly via -git or via pkgbuild locally is a pain). Its main purpose is to track development dependencies as proper dependencies rather than explicitly installed and difficult to later clean up.

If this is grounds for exclusion from the AUR, I'll remove it, but I shared it in the hopes that it would be useful to other ladybird devs.