User blog comment:Kirkburn/Technical Update: April 13, 2015/@comment-452-20150418194704/@comment-452-20150424080540

While I'm normally averse to having words put in my mouth, thanks for mentioning my name Dinoguy1000, as I had overlooked that comment. You can put words in my mouth any time.

I can only assume that more than a couple of users wrote in to Special:Contact asking "why is my notification email blank?"
 * Well, either that or someone realised that spam filters assume that emails without a text-plain portion are spam.

Edit: I tried to look at the source to answer the styled link question, but was unable to confirm that.
 * Double Edit: Keep your eye on avatarLayout.mustache for this change. It still says right now.

Incidentally, here is the edit labelled "Provide a text version of the email.", which I honestly expected to contain more changes, given the previously stated complexity of re-implementing plain-text emails. I am genuinely pleased that it took less code to re-implement plain-text emails than for me to process the HTML emails. :)

Many thanks to garthwebb, and everyone who made this happen.