Author here. This gave me a chuckle. :)

And, yes, that's pretty much it, although "rebimboca da parafuseta" is less obscure than "reticulation of the splines" (if you're Brazilian, anyway).

It is used to denote a fictitious part, which name or function are unknown, of a car engine or any other machine. It was coined in the 70s TV show, and later used in some ads aired during the same period; since then, it's an expression used for humorous effect. It's not very common these days but is unlikely you'll meet someone down here that never heard it.

Aha, not unlike the retro-encabulator:

https://www.youtube.com/watch?v=RXJKdh1KZ0w

Which is of course a riff on the original turbo-encabulator: https://www.youtube.com/watch?v=Ac7G7xOG2Ag

Love that video, I may have shared it with more people than I did the original rick roll video lol

We've got a similar idiom in Spain: "la junta de la trócola" ("trócola's joint", not really translatable, though trócola is apparently a synonym for "polea", "pulley").

It was coined for a cigar brand TV commercial back in the 90s and also alludes to a fictional part, in this case used by a car repairman to fraud a customer into paying more in said commercial.

Out of curiosity, do you know if this translation is used in the Portuguese versions of SimCity?

If I recall correctly, a literal translation is used ("reticulando os splines"). But it's been years since the last alien invasion.

I dont think it would be an accurate translation in that case. the rebimboca is a fictional object while spline reticulation is a fictional action.