I sent ChatGPT in search of the question regarding his alleged resignation, and ChatGPT indicates that the catholic-hierarchy.org citation was wrong, citing a letter written from an official Congregation in Rome, the Congregation of the Clergy, from Cardinal Wright, address to +Lefebvre in 1971, referring to him as the Titular Archbishop of Synnada in Phrygia. It found other instances through the 1970s where +Lefebvre refers to himself as the Titular Archbishop, but by the 1980s he starts using the title "Bishop Emeritus of Tulle", though we're not sure why he switched. But there's absolutely no proof that he resigned his Titular Archbishopric, and much evidence to the contrary. Unforunately, that does pose a serious problem for The Nine, since Canon Law does in fact declare excommunicated, reserved to the Holy See, in a simple mode, anyone who were to take a Bishop, "even a Titular bishops", before lay court, per the 1917 Code of Canon Law. Even if by some shenanigans Montini had stripped him of the title (thus far no evidence for this has been found), The Nine don't consider him a pope anyway, so even such a stripping would have been invalid ... having come from an Anti-Pope.