Please provide contributor attribution

This repository contains third-party contributions covered by either the MIT License or some ambiguous MIT + Share Alike -- I don't know which one it is! Given that errors are typically decided against the drafter, this isn't easily hand waved away. For example, if I tell you my repo is GPLv2 and but paste in the LICENSE text for the GPLv2+ that's my problem, not yours. Regardless of which license applies, attribution is required. Kyle Mitchell has a [line by line breakdown](https://writing.kemitchell.com/2016/09/21/MIT-License-Line-by-Line.html) of the MIT License.

While the core authors of this repository have elected to relicense their contributions under a proprietary license, this has no impact on third-party contributions. On a summarily closed PR one contributor [objected](https://github.com/MetaMask/metamask-extension/pull/9286#issuecomment-678446083) to the new licensing terms. Absent a contributor license agreement, his contributions were incorporated under a license requiring attribution (be that the MIT License or MIT + Share Alike). This is reiterated in the GitHub terms of service:

> Additionally, unless there is a Contributor License Agreement to the contrary, whenever you make a contribution to a repository containing notice of a license, you license your contribution under the same terms, and agree that you have the right to license your contribution under those terms.

Please credit your contributors as required by the MIT License.

No file, test, or entry point is named. Start by reviewing the repository's current license notices and the third-party contributions discussed in the issue, then determine which attribution requirements apply. Done means the repository credits contributors as required by the applicable license.

Written by the indexing model from the issue text.