By default, vanilla Morrowind (and currently OpenMW) will play music essentially endlessly. No gaps are left between one track finishing and the next beginning, barring player death. Despite the incredible music composed by Jeremy Soule, this may get tiring. There is also the potential for whiplash as combat music ends and an exploration track begins.
The game selects music randomly and without regard for context or location. This "mod" does not change this. It simply adds some extra "music" tracks that merely contain pure silence, in varying lengths. This means that there is a good chance for one of these files to be played whenever an exploration track is called for. The result is that most of the time, whenever either an exploration track ends or combat ends, a semi-random amount of silence will occur.
This simple addition has greatly improved my playtime. Combine it with ambient sound mods, and you have something just a bit closer to a modern audio experience.

Installation instructions:

1. Extract files.
2. Copy contents to Morrowind\Data Files\Music\Explore.
3. Add or remove files to taste. More silence files = greater chance of silence being randomly selected as an exploration track.