Reference to the initial containing block definition should be improved #2292
Description
(I realized this while preparing #2291).
The section on ICB defines the viewport meta tag for FXL referring simply to the CSS Device Adaptation Module Level 1. However, I did not find, in that document, a clear definition for that meta tag. The only one I found was the (informal) §9 which says:
This section describes a mapping from the content attribute of the viewport element, first implemented by Apple in the iPhone Safari browser, to the descriptors of the @viewport rule described in this specification.
In order to match the Safari implementation, the following parsing algorithm and translation rules rely on the UA stylesheet below.
This can hardly be considered as a normative reference. Furthermore, that section lists a number of properties that we do not talk about, not clear whether they are considered as o.k. for FXL (but handling those extras is a significant portion of the section).
I wonder whether we should not simply define the meta tag ourselves (it is fairly simple after all).