Dear Thunderbird Team, I am writing to report a critical issue with the Thunderbird Extension API where it returns stale, cached data instead of live folder contents for Gmail IMAP accounts. Issue Description The browser.messages.list() and browser.messages.query() APIs are returning outdated message data from 2016-2021, completely ignoring the actual current contents of my Gmail IMAP inbox. While Thunderbird's UI displays current emails correctly, the extension API serves permanently cached old data. Evidence of the Bug What Thunderbird UI Shows: Current inbox with emails from today and recent weeks Real-time folder contents Proper folder synchronization What Extension API Returns: Only 100 messages total (artificial limit) Messages exclusively from 2016-2021 No emails from 2022-2025 present Completely ignores current folder contents Technical Details: Profile: /Volumes/Data/Mail Files/Thunderbird/Profiles/aq8q4la7.default-release/ Account: Gmail IMAP (imap.googlemail.com) Folder: account1://INBOX API Used: browser.messages.list(folderId) and browser.messages.query() Steps to Reproduce Set up Gmail IMAP account in Thunderbird Write extension using browser.messages.list() API Compare API results with actual folder contents Observe API returns stale cached data from years ago Debugging Attempted We have tried: Deleting all .msf index files Clearing folderCache.json and global-messages-db.sqlite Removing cache folders (cache/, cache2/, startupCache/) Rebuilding folder indexes Using different API methods (messages.query vs messages.list) None of these resolved the issue - the API continues to return the same stale dataset. Impact This completely breaks any extension that needs to access current folder contents, such as email tracking, automation, or filtering extensions. Request Please investigate why the Extension API serves different (and outdated) data compared to Thunderbird's main UI, and fix the API to return actual live folder contents. Thank you for your attention to this critical issue. Best regards, Hasan