We should all be using a consistent, common version of kconfig-frontends. A snapshot was taken and has never disappeared from internet contrary to other statements it is always been here and will always be here: https://bitbucket.org/nuttx/tools/src/master/
Since the kconfig-frontends project is dead, we can consider that the authoritative source for the tools for our purposes. There we can accept any changes that may be necessary and do not have to be concerned with upstream compatibility.
