Description of lang incorrect

[aphillips]

lang member
https://w3c.github.io/manifest/#lang-member

The manifest's lang member is a string in the form of a language tag that specifies the primary language for the values of the manifest's localizable members (as knowing the language can also help with directionality).

The above description of the lang member should not refer to the "primary language", since that has specific meaning in a language tag. It should just say "language".

The parenthetical as knowing the language can also help with directionality is not correct. Language metadata is used for many things--font selection, spelling correction, hyphenation, styling, and so forth. Voice selection for accessibility is another key use. However, while the language can sometimes be used to help estimate the direction, this is not recommended and, given the use of dir and its default of auto in this specification, should not even be mentioned (as the lang MUST NOT be used to estimate the direction when there is metadata provided). Instead this section should mention the other Good Things that language metadata can provide.