It is purely a guess, but they are not exactly separate products like Fisheye and Agile. It is potentially buried on the product page where you click on the addon tab. Under the Marketplace line, it mentions. the "dev tools". Atlassian could not even spell out "Development". :>).
IDE Connectors are not deprecated. They are still maintained and evolved. There are also no plans to deprecate Connectors.
I don't know why they disappeared from the download page. I will ask around and let you know if I find an answer.
UPDATE: IDE Connectors are back on the products page: https://www.atlassian.com/software
Thanks for signing up for Jira Ops! I’m Matt Ryall, leader for the Jira Ops product team at Atlassian. Since this is a brand new product, we’ll be delivering improvements quickly and sharing updates...
Connect with like-minded Atlassian users at free events near you!Find a group
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no AUG chapters near you at the moment.Start an AUG