Geekspeak I don't understand

[Jon Ribbens]

On Wed, May 13, 2015 at 10:27:10PM +0100, Roland Perry wrote:
> In article <20150513123103.GA25424 at unequivocal.co.uk>, Jon Ribbens
> <jon+ukcrypto at unequivocal.co.uk> writes
> >Is it a corporate computer or similar that might have a root
> >certificate installed by the IT department?
> 
> No, it's my five year old laptop where only I am the administrator.
> 
> Not sure if it matters but about three months ago I wiped the
> Win7-upgraded-to-Win8 installation and did in effect a "factory reset" back
> to Vista.
> 
> I use Facebook multiple time most days (for years), and have never before
> seen any error message like this.

It does seem very peculiar. Also, as far as I can see, Facebook does
not use certificate pinning. Something strange happened. It could be
a bug in Firefox I suppose.