The XMLHttpRequest API should ideally adhere to the WHATWG standard

Our XHR implementation is hugely out of date when compared to modern web browsers.

The standard that our XHR implementation adheres the closest too is the XHR Level 1 standard (by W3C back in 2007): https://www.w3.org/TR/2007/WD-XMLHttpRequest-20071026

But there are still discrepancies between our implementation and the specification above.

Our implementation has the response and responseType members, which were added in XHR Level 2 (2011): https://www.w3.org/TR/2011/WD-XMLHttpRequest2-20110816/

Note that the W3C standard has been discontinued in favor of the WHATWG standard: https://www.w3.org/TR/XMLHttpRequest/

Our XHR implementation should ideally adhere to this standard as well, but if that is too big of a goal, then we could start by dealing with the discrepancies between the qt implementation and the final PRE-WHATWG W3C standard.