@lah7 Just discovered a small issue.
After clicking either Welcome "Subscribe to Welcome updates", or Software Boutique "Retrieve the latest software listings.", if one doesn't enter a password when asked, after closing the usual warning message (seen below)
though no password was entered, ppa.launchpad.net/git-core/ppa/ubuntu is added to Other Software, and the option to subscribe or retrieve updates disappears until this ppa is removed.
If one has previously clicked subscribe/retrieve, entered a password, but later decided to delete the ppa.launchpad.net/ubuntu-mate-dev/welcome/ubuntu from Other Software.
Then performs the steps outlined above, the ppa.launchpad.net/ubuntu-mate-dev/welcome/ubuntu is added again even though no password was entered.
Furthermore, after clicking subscribe/retrieve, then clicking Cancel on the Updating Cache pop-up, the ppa is still added.