[TexasGator]

(c) Exceptions

(1) False return

In the case of a false or fraudulent return with the intent to evade tax, the tax may be assessed, or a proceeding in court for collection of such tax may be begun without assessment, at any time.

(2) Willful attempt to evade tax

In case of a willful attempt in any manner to defeat or evade tax imposed by this title (other than tax imposed by subtitle A or B), the tax may be assessed, or a proceeding in court for the collection of such tax may be begun without assessment, at any time.

(3) No return

In the case of failure to file a return, the tax may be assessed, or a proceeding in court for the collection of such tax may be begun without assessment, at any time.

[Raycpa]

Those are extensions of time to assess a tax. The ten years is from the date tax is assessed.