Ubuntu – What does the Ubuntu Foundation do

The core OS of Ubuntu is committed to remaining completely free (financially and freedom wise). It has a repository for partner and non-free software add-ons. Canonical is also enabling optional "pay for" software in the software center. It does not exist in the Ubuntu "Main" repository.

Services like Ubuntu One are merely branded as such for clarity, and their client side software are indeed free. The subscription services that go along with Ubuntu is part of Canonical's business model, which will eventually make the company profitable.

Who decides a distro should become official flavour?

The Ubuntu Technical Board. From the Ubuntu Wiki page on recognized flavours:

Guidelines to have an image added to the dailies

• Official Flavor has been approved by Tech Board
• All packages are publicly available in Launchpad Archive (Main or Universe)
• Launchpad bug infrastructure is monitored and updated for tracking defects related to packages in an image.
• IS has signed off that there is sufficient space to support image builds and publishing
• Release team member lined up to work with team to debug adding it into servers.
• Community member lined up to test image and provide feedback at milestones.

Guidelines to become and remain a recognized flavor:

• Image has track record of community interested in creating, supporting and promoting its use.
• Leading members have signed Ubuntu Code of Conduct.
• One or more developer with upload rights.
• Flavor lead identified and responsive though 6 month cycle.
• Flavor QA lead (may be different from flavor lead) identified to coordinate testing of image at milestones during release.
• Follow the milestone and release processes.
• Best effort support from flavor community for security updates and high priority bug fixes for default 9 month support period.
• If flavor ceases to do active releases for consecutive cycles, release team may request the TechnicalBoard review whether it should remain recognized flavor.

What kind of support do they receive from Canonical or/and Ubuntu community? What privileges do "official flavours" have over unofficial derivatives of Ubuntu like Linux Mint, Elementary OS, Deepin OS,etc.?

From the same Ubuntu Wiki page:

Resources and Services that Canonical provides for Recognized Flavors:

Infrastructure

• status.ubuntu.com for work item tracking at flavor and individual level.
• launchpad mail list support for project communication.
• Ubuntu Security team will help the flavor maintainers distribute security updates to their users, by reviewing and sponsoring any updates they wish to provide.
• Notification of vulnerabilities can be provided by Ubuntu Security team to flavor maintainers, if universe package list to monitor is provided.
• Minimum of 1 person is offered sponsorship to UDS

Daily ISO build and publish

• Use of launchpad build infrastructure.
• Daily publishing of builds on cdimage.ubuntu.com
• Best effort help from foundation and release team members on requested rebuilds and analysis of build failures.

Coordination with Ubuntu release

• Optional inclusion in Ubuntu development milestone releases.
• Inclusion of image in release manifest if:
  • has been made daily.
  • has been released and tested in at least one beta milestone.
• If image is to be published as part of a release manifest:
  • Images published and available through lifecycle.
  • Inclusion in release announcement (pointers to flavor page)
  • Inclusion in release notes (flavor overview and known issues)
  • Use of the ISO tracker for coordinating community testing of images for milestone releases
• Link to flavor as recognized derivative from Ubuntu site http://www.ubuntu.com/project/about-ubuntu/derivatives
• Weekly meeting for sharing status and clarifying dependencies between teams.

And, of course, only official flavours are supported here on Ask Ubuntu.