Both Manjaro and its parent Arch Linux aren't distros oriented to pure FOSS. The community repository contains a mix of open and closed source applications. And there's AUR to build your own custom packages, which most of them are just a PKGBUILD file.

The PKGBUILD downloads the source, patches it (if required) and compiles it to create the desired package. If the package is closed source it just downloads the binaries and repackages the result as a Pacman package.

So they can offer both open and closed source editor suites and you're free to install whatever you want. I've tried several office suites and FreeOffice is quite faster than LibreOffice actually. I've also tried one suite which was an electron app (OnlyOffice) and LibreOffice felt faster than a plane compared to it.