Uncompress compressed messages in Maildir mailbox?

Some time ago I enabled compression on incoming messages, so LMTP delivered messages were compressed. Good idea in terms of disk space, but now I cannot uncompress any of these messages even when I need to!

I was using this setting:

plugins { zlib_save = lz4 }

and now I can see this string at the beginning of each message file - "Dovecot-LZ4", so no other software can uncompress them for me.

Please advise, how can I uncompress message file in Maildir mailbox when I need to access its contents directly?