This is an enclave of the province of Burgos within Alava, and it's called Condado de Treviño It is not so much demanded by the nationalists as wishing, by itself, to be incorporated to Alava because it is several hours away from the city of Burgos but right next to Vitoria.

It would make a whole lot of sense for them to switch, but the last time they tried the PP national and regional (in Castilla-León) government would not allow them to hold a referendum on the issue, and also it would probably bring even more non-Basque nationalists into Alava (though I'd have to substantiate this with election or poll data).

guaranteed to evoke a violent reaction from police is to challenge their right to "define the situation." --- David Graeber citing Marc Cooper