https://d.maxfile.ro/exnhjijhaf.mp3
For reference on how to convert the webm to mp3, just use VLC player for a quick and easy way to do it.
It's there at 0:39 and also listed on AniDB:
>Onihei: Edo wo Hashiru
I've removed this post for now, could you resubmit it please with the song in the title? Thanks!
You can try a cloud converting website like this one. There's a few of them that allow "upload from URL" which basically means they are the ones that download the files into their server and convert the file for you.
For that specific website that I linked, you click on the arrow button next to the select files, paste the webm URL, click the wrench and I recommend "Audio Variable Bitrate" setting as "Constant Bitrate" and "Audio Bitrate" setting as "320kbps".