There is a section with the key reasons it was picked, in particular:
"Relatively compact implementation – QuickJS is slightly more fatty (by 100 kb) but still in acceptable range. For the note: full version of V8 is about 40 mb – 5 times larger than Sciter itself"
40mb is just nuts. These days, jlink would allow me to shrink a Java JVM down to something like that. And that would already include some nontrivial batteries, which Javascript doesn't AFAIK.
Pure V8 - yes, close to 8 Mb - that is still larger than whole Sciter that beside of script VM contains HTML/CSS/Graphics, etc.
40 Mb came from Node.JS distribution (V8 + native runtime = node.exe).
Sciter is more comparable to NodeJS as it includes good chunk of NodeJS alike runtime too.
While I appreciate the conscious size-saving effort, I need to ask: is 30 MB difference that big of a deal for desktop applications nowadays? A random Electron app that I download will easily take up hundreds of MBs disk space.
I personally don’t think it’s acceptable and the disregard for files sizes generally extends to disregard for RAM usage which is even more unacceptable. Sadly I don’t really have a choice regarding using most of these apps.
Is it even possible to distill V8 into a single Windows DLL anymore? The version I use was about 3.5 MB in 2013. I tried updating it a couple of years ago, but quickly gave up and backed away, groping for the doorknob.
It's possible though not straight-forward. React Native Windows seems to have a version of V8 wrapped with JSI (for use in React Native) though by the looks of the project, it appears to be only used internally and not really meant for stand-along consumption: https://github.com/microsoft/v8-jsi
"Relatively compact implementation – QuickJS is slightly more fatty (by 100 kb) but still in acceptable range. For the note: full version of V8 is about 40 mb – 5 times larger than Sciter itself"