Almost all CPU cores are from MAME... this is fbalpha, not FinalBurn.
See here:
https://www.fbalpha.com/license/
FB Alpha is based on Final Burn (formally at
http://www.finalburn.com), see additional text below.
Musashi MC68000/MC68010/MC68EC020 CPU core by Karl Stenerud (
http://www.mamedev.org).
A68K MC68000 CPU core by Mike Coates & Darren Olafson (
http://www.mamedev.org).
Z80 CPU core by Juergen Buchmueller (
http://www.mamedev.org).
ARM CPU core by Bryan McPhail, Phil Stroffolino (
http://www.mamedev.org).
ARM7 CPU core by Steve Ellenoff (
http://www.mamedev.org).
H6280 CPU core by Brian McPhail (
http://www.mamedev.org).
HD6309 CPU core by John Butler, Tim Lindner (
http://www.mamedev.org).
I8039 CPU core by Mirko Buffoni (
http://www.mamedev.org).
Konami CPU core by MAMEdev (
http://www.mamedev.org).
M6502 CPU core by Juergen Buchmueller (
http://www.mamedev.org).
M6800/M6801/M6802/M6803/M6808/HD63701/NSC8105 CPU core by MAMEdev (
http://www.mamedev.org).
M6805 CPU core by MAMEdev (
http://www.mamedev.org).
M6809 CPU core by John Bulter (
http://www.mamedev.org).
NEC V20/V30/V33 CPU core by MAMEdev (
http://www.mamedev.org).
PIC16C5X CPU core by Tony La Porta (
http://www.mamedev.org).
S2650 CPU core by Juergen Buchmueller (
http://www.mamedev.org).
SH-2 CPU core by Juergen Buchmueller (
http://www.mamedev.org).
TLCS90 CPU core by Luca Elia (
http://www.mamedev.org).
ADSP21XX CPU core by Aaron Giles (
http://www.mamedev.org).
AY8910/YM2149 sound core by various authors (
http://www.mamedev.org).
C6280 sound core by Charles MacDonald (
http://cgfm2.emuviews.com).
DAC sound core by MAMEdev (
http://www.mamedev.org).
ES8712 sound core by MAMEdev (
http://www.mamedev.org).
ICS2115 sound core by O.Galibert, El-Semi (
http://www.mamedev.org).
IREM GA20 sound core by MAMEdev (
http://www.mamedev.org).
K005289 sound core by Brian McPhail (
http://www.mamedev.org).
K007232 sound core by MAMEdev (
http://www.mamedev.org).
K051649 sound core by Brian McPhail (
http://www.mamedev.org).
K053260 sound core by MAMEdev (
http://www.mamedev.org).
K054539 sound core by MAMEdev (
http://www.mamedev.org).
MSM5205 sound core by Aaron Giles (
http://www.mamedev.org).
MSM5232 sound core by MAMEdev (
http://www.mamedev.org).
RF5C68 sound core by MAMEdev (
http://www.mamedev.org).
SAA1099 sound core by Juergen Buchmueller, Manuel Abadia (
http://www.mamedev.org).
Sega PCM sound core by MAMEdev (
http://www.mamedev.org).
SN76496 sound core by Nicola Salmoria (
http://www.mamedev.org).
UPD7759 sound core by Juergen Buchmueller, Mike Balfour, Howie Cohen, Olivier Galibert, Aaron Giles (
http://www.mamedev.org).
VLM5030 sound core by Tatsuyuki Satoh (
http://www.mamedev.org).
X1010 sound core by Luca Elia, Manbow-J (
http://www.mamedev.org).
Y8950/YM3526/YM3812 sound core by Jarek Burczynski & Tatsuyuki Satoh (
http://www.mamedev.org).
YM2151 sound core by Jarek Burczynski (
http://www.mamedev.org).
YM2203/YM2608/YM2610/YM2612 sound cores by Jarek Burczynski & Tatsuyuki Satoh (
http://www.mamedev.org).
YM2413 sound core by Jarek Burczynski (
http://www.mamedev.org).
YMF278B sound core by R. Belmont & O.Galibert (
http://www.mamedev.org).
These are all based on the old pre-0.172 cores, so they cannot be used for commercial purposes.
You COULD try to replace all the cores be past-0172-MAME-Versions (which are GPL), but then the used CPU will probably be too slow, as these are made for accuracy, not speed.