FWIW, after those large favicons, the next largest long-strings that I'm seeing in my own sessionstore files are for base64-encoded `csp` fields, which are thousands of characters long and stored alongside every URL (sometimes many times for the same tab if we've got some saved bfcache history, I think). Those might be candidates for deduplication or removal, too. (It's not obvious to me why we need to store those, if we're going to have to hit the network [and rediscover the CSP] anyway to re-request the actual site content when we restore the tab... Or, if there are cases where we're reinstantiating the tab from cached data, maybe the CSP could be stored in that same cache rather than in the reserialized-every-15-seconds session-restore data.
Bug 1867137 Comment 4 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
FWIW, after those large favicons, the next largest long-strings that I'm seeing in my own sessionstore files are for base64-encoded `csp` fields, which are thousands of characters long and stored alongside every URL (sometimes many times for the same tab if we've got some saved bfcache history, I think). Those might be candidates for deduplication or removal, too. (It's not obvious to me why we need to store those, if we're going to have to hit the network [and rediscover the CSP] anyway to re-request the actual site content when we restore the tab... Or, if there are cases where we're reinstantiating the tab from cached data (and hence wouldn't rediscover the CSP), maybe the CSP could be stored in that same cache rather than in the reserialized-every-15-seconds session-restore data.