You can clone with
HTTPS or Subversion.
If detected PHP version is less than 5.3:
This notice is meant to teach users about speed+memory advantages of upgrading + maintaining users within the piwik requirements by warning about future requirement that they can prepare at least for 3-4 months.
updating text per Benaka suggestions
In f94aef3: Fixes #3877, add warning message that is displayed if a user's PHP version is less than 5.3.