To change the user agent in Chimera, which effectively allows you to masquerade as an "accepted" browser, you need to add a line to the prefs.js file located in your user's Library -> Application Support -> Chimera -> Profiles -> default -> XXXXX.slt folder, where the X can be anything. First quit Chimera if open and then open the prefs.js file in your favorite text editor and add the line
user_pref("general.useragent.override", "Mozilla/4.0[space]
(compatible; MSIE 5.2; Mac_PowerPC) - Internet Explorer 5.2, Mac");This should be all one line, spaces as written here (convert the "[space]" insert to an actual space character when you remove the line break). Save the file, open Chimera and you can now gain access to the Citibank site (and presumably others that demand a known (yet inferior!) browser.
[Editor's note: As other hints have explained, you should probably place this command in a user.js file in the same location. There's a chance that your modifications to prefs.js may be overwritten by the program, but the user.js file should remain untouched.]

