They list a bunch of companies under the heading "All these companies work with the same technology" on their landing page. I think it's quite scummy, and very non-impressive when you see it.

Simple rule to keep in mind that even math savvy people seem to forget about is that: sqrt(x²) = |x| with bars for absolute value.

For a programmer, it's clear that we have lost the sign information but not the magnitude.

Simple. Makes most sign and solution reasoning explicit instead of implicit when solving quadratics or otherwise working with square roots.

We can try the same with "oil production"

Do you know if the other 20% is oxygen (as was claimed) or if it's air? I just think the latter seems cheaper and more likely.

It is open source, there are just many different ways to do open source code. One example is Lua, which is released as open source but the project is not open - they will not accept contributions from others.