Gutenlypso: create A8c specific file block

[vindl]

Previously we turned off the default file block because it wasn't working properly, and we couldn't adjust the attributes because of security concerns on wpcom:

https://github.com/Automattic/wp-calypso/blob/master/client/gutenberg/editor/init.js#L23

We need to provide a custom version of this block for WPCOM.

[alisterscott]

Is #29328 because of this limitation?

[vindl]

@alisterscott I think that's a separate issue - #29328 (comment).

[supernovia]

Just noting I switched our support document on file blocks back to draft until this is ready.

[supernovia]

And... switched it back to published because we do have a file block in wp-admin ;)

[KokkieH]

Another user searching for a file block in Gutenlypso here

[KokkieH]

And another

[arunsathiya]

3560513-hc

[erricgunawan]

9235887-hc