FM / ru_RU.UTF-8

/usr/share/X11/locale/ru_RU.UTF-8

Name	Size	Mode	Actions
Compose	97	0644	edit dl rm
XI18N_OBJS	345	0644	edit dl rm
XLC_LOCALE	2327	0644	edit dl rm

Edit: /usr/share/X11/locale/ru_RU.UTF-8/Compose (97B)

include "/usr/share/X11/locale/en_US.UTF-8/Compose"