No to your first question since 19.2/16=1.2, but the Golden Ratio φ is 1.618033988749895...
No, and yes (kind of) to your second question. There is no Web Typography Consortium nor are there "regulations" governing typography. However, there is the W3C, but they aren't a regulatory body. They have created a set of international standards/guidelines that include topics such as web accessibility (WCAG - Web Content Accessibility Guidelines).
Here's what they say about line spacing (leading) with regard to accessibility.
. . . to ensure line spacing (leading) is at least space-and-a-half within
paragraphs, and paragraph spacing is at least 1.5 times larger than
the line spacing
It could be argued this value is close to φ. However I don't think it was chosen because of that. More likely because it simply makes lines of text easier to read especially for people with visual impairment.
Many applications use 1.2x line spacing as the default (or auto) setting. But this value is a basic setting to ensure lines of text don't have overlapping or touching ascenders and descenders. It's not as if it's intended to be the value that should be used.
Yes, the term "leading" often used in typography for line spacing comes from the use of thin strips of lead which were used to create spaces between lines of moveable metal type.