There’s a CCP\Eve path below your users’ LOCALAPPDATA. The fastest way to access it is by running
explorer ${env:LOCALAPPDATA}\CCP\Eve
in a powershell, or
explorer %LOCALAPPDATA%\CCP\Eve
dos command prompt to get a filesystem browser on that path. I don’t know where eve installs it’s stuff in linux, but XDG would proposes localappdata to go into ${HOME}/.local .
Inside the eve localappdata, there’s a directory called sharedcache_tq_tranquility, prefixed by an identifier of the eve installation. For most users, there’s only one such path, because there’s only one eve installation on the system.
Inside the sharedcache path, there’s a settings_default path, which contains files named core_user_${userID}.dat and core_char_${capsuleerID}.dat.
Identifying capsuleers is the easier part, as it’s the last URI element a capusleer’s zkillboard’s URL… for example core_char_2115681442.dat relates to https://zkillboard.com/character/2115681442/ . The capsuleer data records stuff like overview setting or channels you’ve joined … be careful not to copy-paste too agressively as it could get your goon intel spy / fake-intel reporting capsuleer into a horde channel where it’s seen by a goon user’s horde spy and stuff like that.
Identifying accounts is harder. The numbers are always serials, so newer accounts have greater numbers, but if you can’t remember in which order you created your alt accounts, close down everything, including the launcher, open the launcher again, start just the account you want to identify, log into your capsuleer, open the setting dialog and set window mode (if it isn’t already), then drag the window to a different position, and close the client and the launcher. You will notice that one of the core_user files has been modified because it’s modification date has been updated to the current time (storing checksums of the files before and after changing the window location of cause works, too). You can use this to identify each of your accounts. The account data stores window locations, but it also stores things like the size of your NEOCON display, which, like the eve window size, if varying, results in different locations of your GUI elements.
In most situations, you want to copy-paste both the account and the capsuleer settings, but not before making sure you aren’t in chat channels that could allow others to identify your alts.