What do these terms stand for on my HTC RUU
A11_UL is the product number for a specific hardware variant of the Desire 510.  Other examples include HIMA_UL for the m9, M7_UL for the m7, M7C_DWG for the China version, etc.

K443 is the version of software (in this case KitKat, Android version 4.4.3). Other codes you'll see here are L50 (Lollipop 5.0), JB (Jellybean), etc. 

SENSE60 means it has v6.0 of Sense, HTC's custom launcher.  I've also seen SENSE55, SENSE50, etc.

Other things indicate the carrier that the ROM was customized for, radio version contained in the RUU, etc.