Historic in the sense that lab126 built Kindle firmware with them.
These are not the exact
compiler builds used by lab126 but are within the same Major.Minor series (different patch levels).
For instances where the same compiler used by lab126 has to be used for a project, these are a good match.
All are the re-distributable tar-ball releases from Code Sourcery (now: Mentor Graphics).
Note: The "self installer" releases are limited distribution bundles, for those you have to go to the Mentor Graphics web-site.
All of the following are mirrored at: http://drpbox.knetconnect.com/KeK
K3-v3.2.1 (probably any of the K1..DX, ARMv6 Kindles) :
No "Getting Started" and "Changes" README for this one.
K5-v5.1.0 (probably any of the K4 and K5, ARMv7 Kindles):
Currently the most recent public release:
There is a delay of typically 6 months between when a CS/MG development environment is released for sale and when the public copy of the tool chain is posted.
This source of public, cross-compile tool chains is always a bit "old".
On the other hand, these tool chains have been generating code for paying customers world-wide for six months.
That's better verification than any in-house Q.A. department could do in their wildest of dreams.