Meltdown and Spectre in Debian

I'll assume everyone's already heard repeatedly about the Meltdown and Spectre security issues that affect many CPUs. If not, see meltdownattack.com. These primarily affect systems that run untrusted code - such as multi-tenant virtual hosting systems. Spectre is also a problem for web browsers with Javascript enabled.

a short, to the point, update on the status in Debian