Currently, once you reach a sufficient level of infiltration with an alien race, you get a detailed tech breakdown of all their techs. This is potentially useful information but it is currently organised poorly in one large chunk of comma-separated text that does little to present the player with the most salient information, which fits the overall development of espionage in the game: unfulfilling.
Here are a few ideas, not necessarily mutually exclusive
* Chop the list in two blocks, one with tech that you already have, one with tech you do not. Hey, it is the espionage section - let the player know just which tech advantages the opponent has over himself without forcing him to crossreference the list with his own tech list - that's what computers are for. It also makes topical sense - the tech you do not have is the tech that your operatives might possibly steal. This would be a quick-and-dirty improvement.
* Colour techs in the list according to their status (would work equally well with one block as now or two as suggested above):
-- white: you have this tech already
-- red: you lack this tech but you have a better tech than this in its tech-subtree
-- green: you lack this tech and you do not have a better tech in its tech-subtree
A bit more work but potentially more informative.
* Sort it topically like in the tech tree.
Probably something for an expansion where espionage gets overhauled completely. That area of the game really is underdeveloped as is.
- oh, and before anybody says that "you can just open the diplomacy window and check which techs they'll trade", let me note that 1) That does not address the issue that the tech list is a mostly useless mess in the espionage view, and 2) That does not work in non-techtrading games (which, incidentally, are the games where this information is most important since it is harder to get techs from others)