This page aims to document the Unicode coverage of all the fonts (including non-free ones) in Debian. It was created using fontforge, font-manager and gucharmap. You should also read the DebianInstaller/GUIFonts page to find out about the fonts used by the installer.
Please add any fonts which might fill in some of these blocks to the Fonts/Missing page.
TODO: automatically create this page based on the latest unicode-data package as well as all fonts in Debian unstable, using the fonts review:
https://pkg-fonts.alioth.debian.org/review/
Quick test
Firefox seems to render all Wikipedia languages:
http://meta.wikimedia.org/wiki/List_of_Wikipedias
https://phabricator.wikimedia.org/diffusion/MW/browse/master/languages/data/Names.php
Incomplete blocks
Arabic extended-A: U+08B8 and U+08D4 to U+08E2 only available in Unifont
Arabic mathematical alphabetic symbols: U+1EEF0 and U+1EEF1 only available in Unifont Upper
Armenian: U+058D and U+058E only available in Unifont
Combining diacritical marks supplement: U+1DFB only available in Unifont
Elbasan: U+10500 and U+10502 to U+10527 only available in Unifont Upper
Enclosed alphanumeric supplement: U+1F19B to U+1F1AC only available in Unifont Upper
Enclosed ideographic supplement: U+1F23B only available in Unifont Upper
Georgian: U+10C7, U+10CD and U+10FD to U+10FF only available in Unifont
Georgian supplement: U+2D27 and U+2D2D only available in Unifont
Kannada: U+0C80 only available in Unifont
Khojki: U+1123E only available in Unifont Upper
Limbu: U+191D to U+191E only available in Unifont
Malayalam: U+0D4F, U+0D54 to U+0D56, U+0D58 to U+0D5E and U+0D76 to U+0D78 only available in Unifont
Miscellaneous symbols and pictographs: U+1F57A and U+1F5A4 only available in Unifont Upper
Miscellaneous technical: U+23FB to U+23FE only available in Unifont Upper
Myanmar extended-A: U+AA7C to U+AA7F only available in Unifont
Old Hungarian: U+10C81, U+10C89, U+10C8B, U+10C90 to U+10C92, U+10C94 to U+10C98, U+10C9D to U+10C9F, U+10CA1, U+10CA8, U+10CA9, U+10CAC, U+10CC0 to U+10CF2 and U+10CFA to U+10CFF only available in Unifont Upper
Old Permic: U+10351 to U+10354, U+1035A to U+1035E, U+10363 to U+10365, U+10368 to U+1036C, U+1036E and U+10370 to U+1037A only available in Unifont Upper
Sinhala: U+0DE6 to U+0DEF only available in Unifont
Supplemental punctuation: U+2E43 only available in Unifont
Supplemental symbols and pictographs: U+1F919 to U+1F91E, U+1F920 to U+1F927, U+1F930, U+1F933 to U+1F93E, U+1F940 to U+1F94B, U+1F950 to U+1F95E and U+1F985 to U+1F991 only available in Unifont Upper
Transport and map symbols: U+1F6D1, U+1F6D2, U+1F6F4 to U+1F6F6 only available in Unifont Upper
Vedic extensions U+1CF8 to U+1CF9 only available in Unifont
Completely empty blocks
Some blocks have bitmap glyphs available in Unifont and Unifont Upper, noted with an asterisk (*) below.
Adlam (U+1E900...) *
Ahom (U+11700...) *
Bassa Vah (U+16AD0...) *
Bhaiksuki (U+11C00...) *
Caucasian Albanian (U+10530...) *
Chakma (U+11100...) *
Cherokee supplement (U+AB70...) *
Cyrillic extended-C (U+1C80...) *
Duployan (U+1BC00...) *
Glagolitic supplement (U+1E000...) *
Grantha (U+11300...) *
Hatran (U+108E0...) *
Ideographic symbols and punctuation (U+16FE0) *
Khojki (U+11200...) *
Khudawadi (U+112B0...) *
Mahajani (U+11150...) *
Manichaean (U+10AC0...) *
Marchen (U+11C70...) *
Mende Kikakui (U+1E800...) *
Miao (U+16F00...) *
Modi (U+11600...) *
Mongolian supplement (U+11660...) *
Mro (U+16A40...) *
Multani (U+11280...) *
Myanmar extended-B (U+A9E0...) *
Nabataean (U+10880...) *
Newa (U+11400...) *
Old North Arabian (U+10A80...) *
Osage (U+104B0...) *
Pahawh Hmong (U+16B00...) *
Palmyrene (U+10860...) *
Pau Cin Hau (U+11AC0...) *
Psalter Pahlavi (U+10B80...) *
Sharada (U+11180...) *
Siddham (U+11580...) *
Sinhala archaic numbers (U+111E0...) *
Sora Sompeng (U+110D0...) *
Sutton signwriting (U+1D800...)
Takri (U+11680...) *
Tangut (U+17000...)
Tangut components (U+18800...)
Tirhuta (U+11480...) *
Warang Citi (U+118A0...) *
Some conscripts in the ConScript Unicode Registry (such as Klingon, Tengwar and Visible speech) have bitmap glyphs available in Unifont CSUR and Unifont Upper CSUR.