I seen this URL - does builds refer to total download numbers (so for example 456 builds/downloads in last 24 hours and 6794 downloads in last 30 days?)
I'm doing a thesis on FOSS (free-and-open source software) and one of the projects I'm discussing is OpenWRT so wondered if that represented download figures (at least of builds at openwrt.org)?
Yes, those are the build counts partitioned up by release, platform, target, build tool... The Firmware Selector is the ofs entry on the bottom right graph. If you click on the various legend entries, you'll see the build counts for each of the various tools by version.
Sorry, I skipped this part. No, the ASU server's statistics only represent custom builds, not total downloads. The main download site will have quite different numbers, as people grab the base images directly from there. (And then there are those who use either image builder or a full dev environment to bypass all of above.)
https://downloads.openwrt.org/ I don't know of anywhere that reports stats for this (but then I haven't looked, either).