The packages you find on this site are all generated from the versions available at The Document Foundation hosting.
- still and fresh: http://download.documentfoundation.org/libreoffice/
- old: http://downloadarchive.documentfoundation.org/libreoffice/
- pre-releases: http://dev-builds.libreoffice.org/pre-releases/
- daily: http://dev-builds.libreoffice.org/daily/master/Linux-rpm_deb-x86_64@86-TDF/
We use a 64-bit Ubuntu OS (18.04 at this time) and a script we need to simplify the construction you find available github: