Ubuntu font package fonts-sil-mondulkiri-extra

You can install these fonts by opening a terminal and executing sudo apt-get install "fonts-sil-mondulkiri-extra"

Khmer Busra Bunong font family with style Normal
/usr/share/fonts/opentype/mondulkiri/Mo5V56Bu.ttf

Khmer Busra diagnostic font family with style Normal
/usr/share/fonts/opentype/mondulkiri/Mo5V56di.ttf

Khmer Busra dict font family with style Normal
/usr/share/fonts/opentype/mondulkiri/Mo5V56dc.ttf

Khmer Busra dot font family with style Normal
/usr/share/fonts/opentype/mondulkiri/Mo5V56do.ttf

Khmer Busra high font family with style Normal
/usr/share/fonts/opentype/mondulkiri/Mo5V56hi.ttf

Khmer Busra MOE font family with style Normal
/usr/share/fonts/opentype/mondulkiri/Mo5V56MO.ttf

Khmer Busra xspace font family with style Normal
/usr/share/fonts/opentype/mondulkiri/Mo5V56xs.ttf

Khmer Oureang font family with style Normal
/usr/share/fonts/opentype/mondulkiri/Mo9V55.ttf

Khmer Ratanakiri font family with style Normal
/usr/share/fonts/opentype/mondulkiri/RataV53.ttf