Some personal notes about all of the different filetypes in the game:
hkx (havoc)
pam
pami
pamlod
prefab (reflection)
xml (text)
pbd
pcg
dds (texture)
meshinfo (reflection)
paa
pat
imp
impostor
material
technique
pasound
bnk (audio)
wem (audio)
pae (parc, reflection)
paem (parc, reflection)
parg (reflection)
pasg (reflection)
seqmt ! ???????
binarystring ! (u16 count, u8-cstrings)
pabgb ! (raw table entries)
pabgh ! (u16 count, count (var key, u32 pabgb_off))
linkedsceneobject
questgaugecount
binarygimmick
binarygimmickcacheddata
binarygimmickframeevent
nav
road
roadsector
roadidx
save (save template)
pab
pac
paasmt
pappt
paccd
motionblending
pabc
pabv
mi
papr
pamt
txt
pma
paac
paa_metabin (reflection)
paatt
paacdesc
paprojdesc
paproj
pashv
pamhc
pathc (texture header cache)
pas
ies (color)
spline
spline2d
dat (data blobs, unk bufferinfo)
ani
png (png)
ttf (font)
mp4 (video)
cur (cursor)
css (css)
thtml (template html)
html (html)
pai
paseq (custom header, reflection)
uianiminit (custom header, reflection)
paschedulectx
paseqh
paseqc (reflection)
pastage !!!! script
paschedule
paschedulepath
palevel (parc, reflection)
levelinfo
pampg
padxil (shaderblobs)
paloc