Localisation/problematic languages

This is a very draft list of language codes that may have various issues and require careful testing when deploying new features:

project in limbo
aa

za

script variants
ady

ady-cyrl

kbd

kbd-cyrl

kk-*

ks-*

ku-*

tg-*

tt

ug

redirect weirdness
aln

be

be-tarask

be-x-old

crh-latn

crh-cyrl

crh

bh

bho

gan

gan-*

gom-*

ik

ike-*

iu

lzh

nds

nds-nl

shi-*

simple

sr-*

zh

invalid code
als

not-so-valid code
bat-smg

cbk-zam

split from an earlier project
azb

similar names
ckb

ia

ie

koi

kv

pa

pnb

sa

sah

sk

sl

politics (definition of official language etc.)
fa (prs in .af)

tl (fil in CLDR)

different name in langdb
jbo

tet

hak