[jjd-uk]

My understanding is similar to asciidisco, that linking to Widevine from outside Chrome requires a License from Goggle, so currently those add-ons using Widevine via Inputstream are breaking the Terms of Service (TOS) which is the contract you agree to when downloading Chrome, so if anything it is a civil matter (contract law) rather than criminal (where criminal is normally what we refer to as illegal). However as civil proceedings such as takedown notices may come from from violating the TOS, this is why you won't find these add-ons in the official repo or any support threads on this forum.

In theory we could apply for a License, however whether we would get a License if being used to access Netflix, Amazon etc would be not be certain.