Some Touhou fangames use “Carnival” in their name, e.g., Touhou: Carnival of Nightmares (lost media). This could be a shared among developers with a Switch devkit title ID.
No official game by this name exists. Fangames like Touhou Kobuto V: Burst Battle or Touhou Genso Wanderer use different naming conventions. This could be: Touhou Spell Carnival -01005C601EE64000--v0--US...
That game has a “spell practice” mode and competitive play, often jokingly called a “spell carnival” by fans. The string might be a renamed to look like a Switch title. Some Touhou fangames use “Carnival” in their name, e
The technical identifier refers specifically to the US version of the game on the Nintendo Switch. A New Genre: Bullet Hell Tactics Touhou Spell Carnival -01005C601EE64000--v0--US...
Borrowing from classic Touhou mechanics, players can "graze" past bullets to gain advantages.