TIL There’s a county in Texas named after Bandera
Not really, it's named for the Bandera Pass, from the spanish word for "flag". Though the etymology is the same since most slavic languages have the word "bandera" as synonym for flag, coming presumably from italian.
i thought that the common word for flag was "znamę"
It's more for "sign" or "symbol", in modern polish it even means "birthmark" (with "znak" for sign).
More common is its alternative version meaning "to know".