Home Assistant itself uses the Apache 2.0 license, which is pretty permissive. It doesn't impose much requirements on derivative works, so it can use a dependen

Home Assistant itself uses the Apache 2.0 license, which is pretty permissive. It doesn't impose much requirements on derivative works, so it can use a dependency with a restrictive license without problem. However, this would become problematic if Home Assistant also uses a GPL dependency (which it probably does). That dependency would impose a requirement that all other libraries used by Home Assistant use a GPL-compatible license (which his license likely wouldn't be).