This analyzer fixes a Salesforce "quirk" where the property activateRSS is undefined on a retrieve for any Installed Packages.
What triggers this problem analyzer?
Selecting any Installed Packages with the activateRSS value as undefined will cause this analyzer to run.
What problem is it solving?
As of Summer '18 (v43 of the metadata API), Salesforce requires the activateRSS value to be defined when adding or editing Installed Packages. Whenever a retrieve of the data is made against a Salesforce org or a sandbox, the value returned will always be undefined. From Salesforce's documentation:
Validation or deployment to Salesforce will fail unless you have defined activateRSS to be true or false.
How does it work?
Gearset will offer the option to use set the value of activateRSS to be false (the Salesforce default). This will allow you to deploy the changes to Salesforce.
As we have no way of knowing if activateRSS was ever set to be true, if you do want to set as true, you'll need to redeploy the Installed Package (typically in installedPackages/NAME_OF_PACKAGE.insalledPackage) with something like the following:
<?xml version="1.0" encoding="UTF-8"?>
<InstalledPackage xmlns="http://soap.sforce.com/2006/04/metadata" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<activateRSS>true</activateRSS>
<versionNumber>1.0.0</versionNumber>
</InstalledPackage>