I believe the maximum storage is domain based…i.e. each domain gets x amount of data.
But what about when a user switches between browsers?
Do they use two completely separate spaces and similarly separate maximum data amounts.
Secondly,
is localStorage.a in Browser 1 different from localStorage.a in Browser 2?
Similar SO
What is the max size of localStorage values?
HTML5 localStorage size limit for subdomains
Reference
Browsers vendors won’t implement shared localStorage. Each browser that supports localStorage will have an independent instance of however it has been implemented.