coolant colors - what is blue?

[Livolsi, Stephane]

Thanks for the answers. General consensus is that it is Pentosin brand
from the dealer, which makes sense as the car received most of it's
service at a dealer before I got my grubby hands on it.

Step 2.  It was -35C this morning, expected to be about the same
tonight.  I want to boost the mixture a bit (seemed a bit slushy this
morning)  Can I add some green stuff, or not?  I really, REALLY do not
want to do a drain and fill at -35C as I don't have a garage so I'd like
to just take a bit out and add some but I don't think I can get the blue
stuff around here.
Any comments on compatibility of blue stuff with green stuff?

Regarding the weather, it has been in the -30s for the last couple days
and expected to continue for a couple more.  The long term forecast
calls for rain in about a week. Go figure!