Thunderbird - All message filters missing after recent upgrades.

No idea what has happened or when as I have not used this machine for a few days and there was a stack of updates required but when I opened Thunderbird today all my message filters had gone.
Any idea where I might find them?
The filters are still present and working in another machine. What file do I have to copy over to put the filters back into the broken system please?
Many thanks,

Each mailbox has it’s own rules file, named “msgFilterRules.dat”, located within the TB profile directory below “mail”

for example …/mail/mailbox-name/msgFilterRules.dat

Hi Paul,
Not as simple as that it seems. I have this:-

/home/alastair/.thunderbird/a3nxxxxx.default/Mail/Local Folders/

but the file has only to lines with a total of 25B.
I was looking in wrong place but found them now thanks. They were in ImapMail and there are several but only two with kBs of data.
Many thanks.

My filters are located at:

...........\foxxxxxx.default\Mail\Local Folders\msgFilterRules.dat

but be aware that POP and the local account are under …\Mail… but IMAP accounts are …\ImapMail… and that the filters are on an per account basis.