In several places I've seen reference to the Buran automated landing where it supposedly did a go-around and came in for a second landing attempt. I was under the impression that the Buran was unpowered and therefore didn't have any ability to fire engines to regain speed (and therefore altitude) for another landing attempt. Is this go-around an urban legend, or am I mistaken about what Buran was capable of doing on landing?
Unlike Space Shuttle, Buran could cary Saturn AL-31 jet engines. The testing version had four such engines and used to take off and then fly under own power during the tests. Hence it so should have been capable of go-around. The powered landing increased the safety of Buran in comparison to Space Shuttle (source).
Here it is possible to find the description of the jet engine system of Buran. This source names the engines as АЛ-31Ф (Su-33 has the same). It says two engines were foreseen for the space going version, and this would have not been sufficient to take off under own power. Each engine had the maximal thrust of 7770 kgf (afterburners were removed). The two extra engines of the take of - capable prototype were more powerful (12500 kgf).
The source also says jet that engines were not installed during the only space flight 15 November 1988 while there were non-functional engine controls in the cockpit. The engines were not ready yet.
Hence most likely the sources OP references talk about some go-around of the mentioned four - engine testing prototype, not about the go-around of the Buran returning from space.
The space going version of the Buran space shuttle was not capable of go around maneuver.