ObsidianVersionDownloads.apk?

Type: string

The public Android .apk URL. Published as a GitHub release asset named uniformly Obsidian-<version>.apk — the asset first appears at 1.5.8 and is hyphenated from the start, so it has no dot-separator era to guess around (unlike the desktop installers installer-asset.ts handles).

There is deliberately no catalyst counterpart. Unlike the desktop catalyst asar, the mobile catalyst build is not published at a URL at all: Obsidian distributes it through a Discord-gated channel, per https://obsidian.md/help/early-access. What this table can carry for a catalyst mobile build is its changelog — ObsidianVersionChangelogUrls.mobileCatalyst.