New in Supercharge 1.4.0:

Copy a direct link to a message in the Mail app.

https://sindresorhus.com/supercharge#mail-copy-message-link

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It also lets you show the system sound menu bar icon only if the sound is muted.
@sindresorhus Thanks for the update! It would be helpful to be able to assign a keyboard shortcut to Copy Message Link that's only active when in the Mail app.
@timstringer Added in the latest update (it's under the "Tweaks" settings tab).

@sindresorhus Thanks very much for adding a keyboard shortcut for "Copy message link" in Mail!

p.s. I plan to demo this feature in my upcoming Taming Email with OmniFocus 4 course on @learnomnifocus.