Spelling used to be a big one. E.g. in the opening sentence of the article, the word "otimização" would've been an obvious sign it was Brazilian, because the usual European Portuguese spelling was "optimização" — we had a bunch of silent consonants like that all over the place, but most of those got removed once Portugal started adopting the 1990 orthographic agreement[0]. Speaking of spelling differences, now that I'm re-reading, I could've noticed it was Brazilian from "ingênua" in the first section (would've been "ingénua" in European Portuguese).

A common pattern in the readme is the use of "em um" ("in/on a" in English), which is idiomatic in Brazilian, but not in European Portuguese, where the contraction "num" would be standard. It's one of the cases that could be attributed to overly stiff academic writing, though.

0. https://en.wikipedia.org/wiki/Portuguese-Language_Orthograph...