The Baofeng GT-3WP has a feature labeled "Cross band reception / transmission". Does that mean it will function as a Cross-Band Repeater?
I have a Baofeng handheld with similar specifications, and the short answer is no, it does not function as a repeater in any way - cross band or otherwise. I would imagine that would be a feature they would be quite specific about.
The long answer is that you can operate between both bands to use a cross-band repeater or satellite. Using software like Chirp, you can program duplex operation with the regular +/- offsets as in columns 3 & 6 of this screen shot using 2M repeaters as an example:
or you can enter your receive frequency and select "split" instead of the +/- offset. You would then enter the frequency of the transmit band in the column usually used for the offset as in this image:
This is the capability they are stating.
The manual for that radio doesn't seem to specify, so I would guess that it is capable of communicating with a cross-band repeater, but probably not capable of acting as one.
Found the manual here: http://s3.image.ro.s3.amazonaws.com/download/GT-3WP-manual.pdf