ETags are another threat to privacy which are used more and more often (also as a part of the famous Evercookie). Thus, it would be great if HTTPSB - beyond its cookie control - would also offer an option to block ETags.

Some interesting links:

https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.19
https://en.wikipedia.org/wiki/HTTP_ETag
https://trac.webkit.org/wiki/Fingerprinting
https://lucb1e.com/rp/cookielesscookies/
https://grepular.com/Preventing_Web_Tracking_via_the_Browser_Cache

Proxomitron is said to be able to block Etags with a specific filter which seems to manipulate the respective response header, see https://prxbx.com/forums/showthread.php?tid=1816

For a Chrome extension, this site might be relevant: https://stackoverflow.com/questions/13700394/how-to-change-response-header-in-chrome