I first noticed Start TV on 2.4 yesterday (12/8) but I think it was added at the beginning of December. I had done a rescan on my one OTA set last weekend (to clear out the mapping for the now-defunct KHLM/43) so 2.4 would have been present at that time—it would not have shown up on my tv otherwise.
Start TV markets itself as a female targeted channel with shows that feature strong female leads. The lineup seems to be a solid mix off-network shows from the past 10-15 years.
The other KPRC subchannels are on Xfinity here in Houston, so I would guess Start would eventually be added as well.
Only other Texas market with Start TV is DFW, airing on KTVT 11.2.