Meaning of the extension .ucode of files in /lib/firmware

I was examining my firmwares and I found files of various extensions:

.ucode .bin .fw .brd .sbcf etc. I searched for .ucode bit got few results whcih talked about missing drivers etc, but did not tell me the purpose of this extension. So that is why I am posting here to know its meaning and why it is used.

PS — Can someone give me some pointers or sources to actually find the meaning of all the different extensions I have found.Below is the whole:

b00
b01
b02
b03
b04
bin
bin-48kHz_i2s_master
brd
bseq
bts
cis
cld
csp
cyacd
dat
db
ddc
dfu
dlmem
dsp
fw
fw2
hcd
hex
img
initramfs
itb
jsn
ldc
mbn
mdt
mfa2
mpg
ncf
nffw
p7s
pkg
ri
rps
sbcf
sbin
sfi
sys
tlv
tplg
txt
ucode
v2
z77