Some notes about the collection, for anyone interested in hacking stuff.
SeiKen DenSetsu 1: each ROM is different, despite being identical with the existing ones, in the game.
SeiKen DenSetsu 2: the french and germanic regions got differences.
The french is tagged as "1.1" in the header, but it is not the same inside the no-intro database.
Both got wrong checksums in the header, while the "BADSNES" and no-intro ones are correct.
Inside the game, both are identical up to the main menu.
SeiKen DenSetsu 3: the regions didn't exist, obviously.
Every one got wrong checksum in the header, and they didn't even changed the regional code, as all of them run in NTSC.
The english locale is the "sk3_a.smc" one, despite the naming.
It is possible to note graphical glitches in the menus, but there is a lot to discuss on the matter as it is running in "high resolution".
It is not a good idea to swap saves between these regions and the japanese: irregular characters lock the game at some dialogues, specially with the third member. Off that, everything else seems normal.
The "sk3_e.smc" looks like some intermediary english version for Europe (naming), but it is "broken": the opening is in japanese; title screen with the "of" off place; bugs at menus and dialogues, specially with named characters. It can be played but the crash probability is high in many places.