If opening a file using font "Times" in Inkscape on a Windows machine without that font installed, it uses Arial for rendering instead. For all the cases I tried, including generic font names such as "serif" and "sans-serif", it defaulted to the best replacement candidate that I know of. 

How is that implemented? Is this logic part of Inkscape itself? Does it use an external library? Does it use some service/interface on Windows (which other apps apparently don't use)?

Most apps do this well on Linux, because they simply rely on fontconfig. But very few apps do well on Windows. 

Good job, thanks :) Sincerely, Thomas