Similar to SendGrid extension and others, a request came in via enwiki to have an extension using the SparkPost API with similar functionality.
See request here: https://meta.wikimedia.org/wiki/User_talk:X-Savitar#Would_you_pleased_to_write_a_sparkpost_email_extension_for_Mediawiki?
In order to execute this request, the following would be necessary;
[X] Do we need just an extension for email delivery like SendGrid for example? yes, per task description.
[X] Request creation of a Gerrit repo for the project
[X] Check request whether repo is created (this can take a few days) - thanks @MarcoAurelio
[X] Build the extension (Extension:SparkPost) - done! PHPUnit tests left
[X] Create an extension page on MediaWiki org documenting this extension - here: https://www.mediawiki.org/wiki/Extension:SparkPost.
[ ] Write PHPUnit tests for the extension - in progress
[X] Do a release of the extension to be deployed - 1.0 and 1.1 are out and already in use.
[X] Maintain this extension over time - definitely, my eye is on it always.