That is not a codeshare. UA is just willing to sell you the connection on LAN.

This is a big change for UA to offer that route on .com, btw. In the past it did not recognize CTG as a revenue destination.

I'm surprised they're not offering more options with *A partner AV. AV has about three times as many daily flights on that route as LAN.

Note that if you route on LAN rather than AV, you will not get any *A benefits, including lounge access in BOG or CTG (and there's a nice new AV lounge at CTG).