Mac OS X 10.5.5 - over 120 fixes - perhaps a 10.6 backport?
Its reported that 10.5.5 has over 120 fixes - a lot of these seem to be core fixes.
Heres some idle speculation: perhaps Apple are backporting changes from their work on 10.6 (Snowleopard)?
This does not seem crazy to me given that Snowleopard is - as we call it at Atlassian - a “engine room” release.
Thats 120 fixes - an extraordinary amount of fixes for a point release…
The “engine room” stuff announced for Snow Leopard is mostly low-level work: new versions of various APIs, smaller footprint and so on. One thing we’ve found on Engine Room is that while it helps fewer bugs get written, it doesn’t really fix bugs itself.
Maybe it’s more that, given the limited scope of Snow Leopard, and the fact the OS X team is no longer working 24/7 trying to get the iPhone OS out the door, they have more resources to throw at bugs and stability issues?