I'm Spanish and it's the first time I see this Twitter account. I don't remember any leak mentioning this account, so I wouldn't give it any credibility. Pretty likely just a joke as mentioned above.
But well, having said so Mercury Steam -a studio from Spain- just released the best selling Metroid game ever (they also developed the best selling Castlevania game ever) so it's fair to assume Nintendo may have asked them another game, and if Switch 2 is planned to be released next year it's fair to assume they already have a prototype kit.
It's also worth mentioning that in Spain there's also studios from Ubisoft, Gameloft, IOI, Infinity Ward, Smilegate, THQ Nordic, Paradox, Mediatonic plus many cool indie/AA teams who work for people like Tencent (Novarama), Epic (Fall Guys), Riot (Tequila) or Devolver (Gris/Neva, Red Strings Club / The Cosmic Wheel Sisterhood) to name a few.
So it's pretty likely that if Nintendo already sent devkits to 3rd parties or 2nd parties (something that it's reasonable), there should be several of them in Spain.
Isn't El analista de bits or whatever it's called known shit posters?
This "El analista de leaks" (the leaks analyst) account isn't related to the "El analista de bits" (the bits analyst) account.
El analista de bits is that other one from a guy who makes DF like comparision tech analysis videos, isn't related to leaks.
The Switch 2 development kit has arrived in Spain.
