Cyrillic fonts:

Type A. Alt

[Reference: codepage 866 (as given in Unicode 1.0, Vol 2, Appendix C).]
The Alt fonts have the Cyrillic letters in the ranges
0200-0237: capitals, 0240-0257,0340-0357: lower case,
0360-0367: some additional letters.

Here we have the alt* fonts (except that the positions 0362-0367 do not
carry upper and lower case e, yi, short u).
However, altc has some additional slavic characters
(and fewer line drawing characters).

Cyr_a8xN follows cp866 in the positions 0200-0257 and
0340-0357. This means that upper and lower case io
(cp866 codes 0360, 0361) are also missing.


Type B. Koi8

[Reference: RFC 1489 for koi8-r, RFC 2319 for koi8-u]

The koi8-r and koi8-u character sets are almost identical.
For the 8 letters in koi8-u, not in koi8-r, see src/koi8.syms.h.

The koi8* fonts here are the koi8 equivalents of the alt*
fonts above; in particular, koi8c-8x16 includes koi8u but
has additional slavic characters.

koi8-14.psf follows koi8r in the positions 0300-0377
(and has some iso-8859-5 symbols in 0240-0277,
and yat, fita, izhitsa in 0200-0202, 0220-0222).
In particular, it does not have the io and IO at
0243, 0263.

qinglong@Bolizm.ihep.su writes:
"BTW, there is no full rfc1489 compliant russian font shipping with `kbd'."
and contributed koi8r-8x8.


Type C. ISO 8859-5

iso05.fN precisely follows iso-8859-5 in all positions
where that norm defines a symbol.
It has no symbols in the range 0200-0237.

880.cp follows iso-8859-5 in the positions 0240-0377
except that the four symbols 0244, 0364, 0371, 0372
[Ukrainian Cyrillic letter ie (upper and lower case),
and Cyrillic small letter lje, nje] are missing.
It has a few old Russian symbols in the range 0200-0202,
0220-222 (yat, fita, izhitsa).
Thus, in spite of its name it has very little to do
with the ibm cp880 (as described in GNU recode).