Why i can't see a "Digispark" in the Boards Manager?

[Lines_of_codes]

*I use Arduino IDE 1.8.9
I open Arduino then Tools-->Board-->Boards Manager
Board Manager, I change "all" to "contribute" then I can't find "Digispark ..."
I don't know why? (Then I install drivers and see but I can't see that too.)

[granzeier]

Did you add the Digistump package to the “Additional Boards Manager URLs”?

(https://digistump.com/wiki/digispark/tutorials/connecting)

I have forgotten this before, and you won't find the Digispark in the Board Manager until you do.