The tools in /crx/ have been around in AEM/CQ land since well before Adobe acquired it, and had most of its current feature set as of 10 years ago on CQ 5.2.
Adobe is finally retiring one of those tools, the “Package Share” utility at /crx/packageshare which we’ve all used on our pre-production environments (or embarrassingly in some cases on production) to download service packs, hotfixes, cumulative fix packs, and other pieces of functionality from Adobe.
AEM 188.8.131.52 (Service Pack 5) will be the last service pack you ever get from Package Share. As of service Pack 5, the Package Share will now be disabled. From this point forward, you’ll be able to download new releases via https://experience.adobe.com/ where you’ll see a “Software Distribution” link on your home page