...instead of the old HTML format. Avoiding the HTML parsing code on first startup is bound to be a win, and JSON is a simpler format anyways. (Some day we might even want to get rid of the html import/export code entirely, too.) We did this in Fennec because it doesn't have access to the html import code: bug 511435

Moving from build config to toolkit/places. We've had moving away from bookmarks.html on our mind when we moved away from bookmarks.html for l10n, given that the actual file format we use for import would be totally ignoring the strings that need to be fed in. We could do something generic inside toolkit/places to bootstrap the places db from either json or even a sql file if empty. Maybe if a pref to a chrome:// url is set or something.

Per policy at https://wiki.mozilla.org/Bug_Triage/Projects/Bug_Handling/Bug_Husbandry#Inactive_Bugs. If this bug is not an enhancement request or a bug not present in a supported release of Firefox, then it may be reopened.