So I was looking at this line, and it said that it had  copolymer and fluorocarbon technologies. So is it a copolymer or fluorocarbon or monofilament. Also, what qualities does it have (sink, float, stretch etc.)? What applications would it be best for?

Its a co-poly...mono core with with fluorocarbon coated exterior.  Hence maybe slightly more density than just plain mono but basically it floats.  Very thin for a flouro coated line, more sensitive than your typical mono.  Very low stretch, impressive in that regard.  Stronger than other straight fluorocarbons I have used in the same pound test.  Overall, an excellent line IMO.  

It's also a softer line as well as being available in clear blue/ flourescent. It is a good line. I'd recommend it.

Worse version of P-Line PF original.

Couple years back I tried it in the 10# & 12# and liked the way it handled and the purplish flo color.  However, it breaks easy on hooksets imo.  I tried both the palomar and improved clinch..same results.  Since then I've went to 12# Seaguar AbrazX and have been happy.  

I sometimes use it in # 15 it doesn't break..

What type of knots should I use with it? Uni Knot, Palomar knot, or Improved Clinch Knot?

What Exactly Is P-Line Cx

It's a Yo-Zuri hybrid wanna be!

Rather than dissect that one line, maybe sharing what you're looking for in a line and application will get you more useful feedback and suggestions. For instance, there was another recent thread about the myth of reduced line stretch of fluoro. If that's a main concern you may want to look at braid. 

I will probably use this line for shallow and medium cranking or topwaters.

I've used many types of line and pline cxx is the best multi purpose line I have come across for baitcasters.  very abrasive, great knot strength for a double uni or palomar.  It can seem a little stiff when you first get on the water, but after getting it wet with shorter cast you can loosen it up and let it fly.  10 lb will handle most applications and you wont go broke using it.

The CXX abrasion resistance is said to be good . If fishing mostly open water 10% Suffix Elite will do fine and handle better. 

What Exactly Is P-Line Cx

It's a Yo-Zuri hybrid wanna be!

I'm with the bosn.  I find Cx to be too thin, too stretchy and too brittle.  I tried 8 and 10 and couldn't trust a knot in either - tight bends kinked it and allows for stressed breaking points. 

I'm with the bosn.  I find Cx to be too thin, too stretchy and too brittle.  I tried 8 and 10 and couldn't trust a knot in either - tight bends kinked it and allows for stressed breaking points. 

 

The diameter of Yozuri hybrid and CX isn't even close for each respective "ratings"

Backing for bait casters. It isn't terrible for spinning outfits, but like braid better for everything besides finesse presentations.