Following infos are available (click on info for the URL):

Info Current value Description
stable 2.1 Stable version.
stable_number 33619968 (0x02010000) Stable version, as number, like plugin API: info_get("version_number").
stable_date 2018-03-18 Date of stable version (format: "YYYY-MM-DD").
devel 2.2-dev Development version.
git 33198327876b34aaced879f8cf5e6f0e47d5dab9 Output of "git rev-parse HEAD" for sources repository.
git_scripts 3a690b37d87d64380f6ef86bc786974568b919d8 Output of "git rev-parse HEAD" for scripts repository.
next_stable 2.2 Next stable version.
next_stable_number 33685504 (0x02020000) Next stable version, as number, like plugin API: info_get("version_number").
next_stable_date 2018-07-08 Approximate date of next stable version (format: "YYYY-MM-DD").
all stable:2.1
stable_number:33619968
stable_date:2018-03-18
devel:2.2-dev
git:33198327876b34aaced879f8cf5e6f0e47d5dab9
git_scripts:3a690b37d87d64380f6ef86bc786974568b919d8
next_stable:2.2
next_stable_number:33685504
next_stable_date:2018-07-08
All infos (one info by line, format: "info:value").

You can fetch these URLs from scripts or other sites.