Bitcoin Knots is one of Bitcoin wallet softwares and it's open sourced.
https://walletscrutiny.com/?platform=allPlatforms&page=0&query-string=bitcoin%20knots


Why did you compare a Bitcoin wallet software with hardfork full node coins?
I see it is a very inaccurate and weird comparison as wallet softwares compare with each other, and different cryptocurrencies compare with each other.

People are free to choose Bitcoin wallet softwares and I can find both Bitcoin Core and Bitcoin Knots with some filters.
https://bitcoin.org/en/choose-your-wallet?step=5&platform=windows&user=experienced&important=control,transparency,privacy,fees&features=full_node