All the commenters suggesting that Proton is just a company and would always give in to legal requests and all other companies and any email provider would do the same, here's some more to add. Yesterday I saw a now invalid toot comment from ProtonPrivacy on Mastodon Social where they wrote that it was Apple who was to blame and that Proton gave the recovery email address only because this was a case of a terrorism suspect suggesting that if that (terrorism) was not the case they would not have given in to the request. Today their comment sadly gives a 404 error. Searching a bit further this article comes up mentioning Proton and Wire :
In the new resolution, the National Audience judge recalls that in January, in a judicial report he issued on the case, he highlighted a conversation from July 12th and 13th, 2020, about the king's visits, which was included in the Tsunami investigative evidence, and of which he admits that until that point he had not made reference in his investigation which extends over the period from 2016 to 2022. Specifically, one of the people under investigation, the Girona businessperson Josep Campmajó, spoke to the figure named Xuxu Rondinaire, with profile @marietadelulllviu, about mobilizations in 2019, using the Wire messenger app. The judge has asked for the identification of this person, information now obtained by the Civil Guard, which details that they used Europol to ask the Swiss authorities for the Wire firm to identify the person behind this pseudonym, with a profile that is also used in Proton Mail, an encrypted email system. In the police cooperation form requesting the information, the Spanish officers indicate to the Swiss authorities that the investigation is for the crime of terrorism.