AAACK I lost all but 2 entries of the Mail/active file

[reader <hput3@fastmail.fm>]

Don't know how it happened but I lost dozens of entries in the
Mail/active file... the groups view shows dozens of asterisks in front
of many many nnml groups.

Short of rolling back to a nifty backup file I DO NOT have. What would
be the next best option?

If the answer is to recreate the `active' file I could use some
coaching on how to proceed.

One example from my exiting active file:

paypal 53 3 y

According to some of the `INN' documentation those entires stand for

     <newsgroup> <high> <low> <status>

The `high' and `low' refers to message numbers in the group


The `y' is one of 5 or 6 possible characters that can tell different
things about the group:

The `y' char in particular means "Local postings and articles from
peers are allowed".

And will appear on all or nearly all the files.  It may be kind of
meaningless in gnus. 

Since the messages are all still in the nnml directories, I can look
thru them and get those `high' and `low' message numbers for the
active file with a little work.

So is generating the active file by hand the best way to go?