In Hollow Knight, if you navigate to the options menu and look at your achievements when first starting the game, you'll see that some of them are secret - that is, they have no description or title.
How many of them are there, what are their descriptions and titles, and how do you get them?
I specifically mentioned the Nintendo Switch platform because according to the Fandom:
The achievments are the same as for PC/Xbox and are listed right underneath that disclaimer you included from the Fandom Wiki.
What the articles says is just that Nintendo Switch lacks a dedicated system for Trophies/Achievments like for instance on Steam or on Xbox so they are displayed in a different manner in the game.
The Secret/Hidden achievments are marked with a green {s} next to the name on the wiki.
In general, hidden achievments are usually tied to story progression or other possibly spoilery things. But can ofc be just secret for the sake of being secretive.
