Sifting through git log core-0.25.0..cut-core-0.26.0 -- core/ right now, release notes forthcoming.

Included in release (I am going to edit these in place, this is just copy-paste at the start):

Breaking Changes

• Switching from httplib2 to requests as the HTTP transport. This is a result of two plus years of work by many people, including the creation of the google-auth Python package. Special thanks to @jonparrott!
  • Remove httplib2, replace with Requests (Remove httplib2, replace with Requests #3674)
  • Removing google.cloud.streaming subpackage (vendored in originally from apitools but our usage was mostly replaced by google-resumable-media). (Removing vendored in google.cloud.streaming. #3654)
• Moving bytes signing helpers from core to storage. (Moving bytes signing helpers from core to storage. #3668)
• Removing get_credentials() from core. (Removing get_credentials() from core. #3667)

New Interfaces

• Add base future package to google.cloud (Add base future package to google.cloud #3616)
• Add operation future (Add operation future #3618)
• Split polling future into its own module (Split polling future into its own module #3662)
• Correctly url-encode list parameters (Fix url encoding of list parameters #3657)
• Add a function to complain about obselete packages. (Add a function to complain about obselete packages. #3724)

Docs

• Fix broken link in error message when trying to use invalid credentials to sign a URL h/t to @SeanBE (update doc reference for setting up a service account #3578)
• Fixing docs links that were broken when moved. (Fixing references to "dead" docs links. #3631)

Packaging

• Fix inclusion of tests (vs. unit_tests) in MANIFEST.in (Fix inclusion of tests in manifest.in #3552)
• Updating author_email in setup.py to googleapis-publisher@google.com. (Updating author_email in all setup.py. #3598)

Not included in release:

• Making all LICENSE headers "uniform". (Making all LICENSE headers "uniform". #3563)
• Shorten nox virtualenv names to avoid hashing. (Shorten nox virtualenv names to avoid hashing. #3585)
• Changing all pypi.python.org links to warehouse links. (Changing all pypi.python.org links to warehouse links. #3641)
• Fix pylint for the main package (Fix pylint for the main package #3658)
• Re-enable flake8 for core package and tests (Re-enable flake8 for core package and tests #3664)

please include

* Fix inclusion of tests in manifest.in (#3552)
* Updating author_email in all setup.py. (#3598)

Since in impacts the distribution package.

Merging, despite the very much broken-ness (the core version is invalid for the upper bounds in all the downstream packages, so they pull from PyPI).