Name: ibus-m17n
Homepage: https://github.com/ibus/ibus-m17n
Open Source: yes
Source: https://github.com/ibus/ibus-m17n/archive/1.3.4.tar.gz
Why?
I only need the m17n for IBus for its pinyin with tone marks implementation which is not available anywhere else. The only other solution would be to work with macros (https://dev.solus-project.com/T1421) or to port a Windows program (such as Pinyinput: https://www.pinyinput.net/) to Linux.
Another alternative could be https://github.com/fcitx/fcitx-m17n but I am not sure whether it has the same "pinyin with tone marks" implementation.