JIRA administrators often need to implement sophisticated workflows that go beyond the built-in capabilities of JIRA. The JIRA Misc Workflow Extensions add-on for Cloud provides extensions that help you to design advanced workflows. 

The add-on provides advanced Post-functions to achieve this purpose with no programming skills. You can tailor your JIRA workflows to meet your need and reduce the user intervention on actions.

Atlassian has made a decision to remove all add-ons that come pre-installed with JIRA Cloud in order to improve the stability, performance, and security of their JIRA Cloud offerings. The new Connect framework, which is the only framework still supported for Cloud add-ons and is available for third party software developers, doesn’t currently offer support for Conditions and Validators.

For information on the features, see: Workflow Extensions for JIRA Cloud