At the bottom ("Accessing the backend") let's look into the file "finance3.js".
Do you see there this line: usdToForeignRates = newUsdToForeignRates; ?
If I understood the things correctly, this is a good memory-leak, huh? Or not?
"For every word I’ve written, five have been discarded. Such is the nature of writing. For every ten
programs I’ve downloaded, tried, and tested, nine have been discarded. Such is the nature of software."
(c) Steven Goodwin
Testers: "Bug report. It is too dark at night and the user can't see anything. Please see the attached screenshot. Assigned to Lord."
Lord: "I tried to reproduce this issue using cats, owls, bats and gentlemen in black velvet too. Cannot reproduce. Closed as 'By Design'."
Testers: "Reopened. Then it seems to be reasonable to show some warning to the user in the evening or even better to turn the user into a cat or an owl. Priority changed to not critical but must be fixed to the next release."
Lord: "Assignee changed to Lucifer. Btw I don't know the next release date."