Page gone. There is a reference here https://en.wikipedia.org/wiki/Grin
Maybe there were once a Mimblewimble wiki page. Generally the wiki is easier to convince if it is done in small steps.
Like
Add a Mimblewimble section on some existing page
Wait for it to "stick"
Extend with grin, and competing, implementations
Find notability
Add references
Make more news
Add news limks
Now the original article is getting "fat" and extracting sone part to a separate page is usually doable. Write in the new article's talk page where it was taken from.
https://en.wikipedia.org/wiki/Grin_(cryptocurrency)