Because Firefox 52 ESR is an "end-of-life" version, it is no longer available on the main Firefox download page. You must access it through Mozilla's official archive or reputable repositories.
: This is the safest source for original, untampered installers. Direct Link : Firefox ESR 52.0 Releases . how to download esr 52 firefox
Firefox ESR (Extended Support Release) 52 is a legacy version of the browser, notably known as the final release to support older operating systems like Windows XP and Vista. While it is no longer supported by Mozilla with security updates, it remains useful for accessing legacy web applications or running on vintage hardware. Because Firefox 52 ESR is an "end-of-life" version,
: A reliable secondary source if you prefer a web-based interface for older software versions. Firefox v52.9.0esr on Archive.org . Step-by-Step Installation Guide Directory Listing: /pub/firefox/releases/52.0esr/win32/ru/ Direct Link : Firefox ESR 52
: The final point release in this branch was 52.9.0esr , available at the 52.9.0esr directory.