How to know what version of PHP is shipped in a release version?

Is there a page or Wiki listing for each Ubuntu release what is the default associated PHP version?

10.04 LTS => PHP 5.3.2

And so on...

There is the packages.ubuntu.com website. It's pretty handy for this stuff.

Here is the current output:

lucid (php): server-side, HTML-embedded scripting language (metapackage)
5.3.2-1ubuntu4.20 [security]: all

lucid-updates (php): server-side, HTML-embedded scripting language (metapackage)
5.3.2-1ubuntu4.20: all

precise (php): server-side, HTML-embedded scripting language (metapackage)
5.3.10-1ubuntu3.7 [security]: all

precise-updates (php): server-side, HTML-embedded scripting language (metapackage)
5.3.10-1ubuntu3.7: all

quantal (php): server-side, HTML-embedded scripting language (metapackage)
5.4.6-1ubuntu1.3 [security]: all

quantal-updates (php): server-side, HTML-embedded scripting language (metapackage)
5.4.6-1ubuntu1.3: all

raring (php): server-side, HTML-embedded scripting language (metapackage)
5.4.9-4ubuntu2.2 [security]: all

raring-updates (php): server-side, HTML-embedded scripting language (metapackage)
5.4.9-4ubuntu2.2: all

saucy (php): server-side, HTML-embedded scripting language (metapackage)
5.5.1+dfsg-1ubuntu1: all

As of Xenial Xerus the keywords string to search is "php". (the version is PHP7)

xenial (php): server-side, HTML-embedded scripting language (default)
1:7.0+35ubuntu6: all
also provided by: php7.0

xenial-updates: Virtual package
provided by: php7.0

yakkety (php): server-side, HTML-embedded scripting language (default)
1:7.0+42: all
also provided by: php7.0

This page lists the different versions of php5 in different release of Ubuntu:

https://launchpad.net/ubuntu/+source/php5

Ubuntu 16.04 LTS (Xenial Xerus) was the first Ubuntu release to ship with PHP 7 instead. So the link changes to:

https://launchpad.net/ubuntu/+source/php7.0