Have now tested Firefox 93/100. 
What a difference to IE score (20/100) 
.
What an eye opener. 
Yes. What this is measuring is standards compliance, of course. An end-user won't usually understand this - if they look at a web page which is coded up for IE then everything will work, and that page will probably NOT work for Firefox, Chrome and Opera. Then the user will complain and say how bad Firefox, Chrome and Opera are, and only buy Microsoft products in future.
This is a very well-known Microsoft business practice. They call it the '3 Es' - Embrace, Extend and Extinguish.
The way it works is that Microsoft waits until a computer business area starts taking off - let us say, software for selling bananas. As it takes off Microsoft buys a company in the 'banana software' business, and joins the standards groups that enable each banana company to work with each other. That's 'Embrace'.
Once Microsoft has understood the way their standards work, it puts out a new program which uses the standards, but adds a few extra features which are non-standard, and which it has patented. And makes those critical to the operation of the system. That's 'Extend'.
The final stage is when Microsoft gives their new program away in a bundle with their operating system. Everybody uses it, and uses the non-standard bits. The other companies try to compete, but all their customers now rely on the non-standard bits, and they can't offer similar non-standard software, because Microsoft has patented it. They go under. That's 'Extinguish'.
Some people still think that Microsoft got to where it is by writing better software...
