I’m glad that U+0466–U+046D CYRILLIC (CAPITAL|SMALL) LETTER (IOTIFIED)? (LITTLE|BIG) YUS are present in Linux Libertine. Unfortunately they are missing in Linux Libertine Bold and Bold Italic.
Also, accents over them are poorly positioned. Demo for characters I need:
$ pango-view --text='Ѧ́ѧ́Ѫ́ѫ́' --font="Linux Libertine 72"