This problem analyzer identifies if the TASK.WHAT_NAME field is present in your XML as there are some cases where it may cause a deployment error in older Salesforce orgs.
What triggers this problem analyzer?
This problem analyzer will be triggered if you try to deploy a layout containing the TASK.WHAT_NAME field (see example XML below) when using API version 46 (Summer 19) or below.
You'll see a message prompting you to remove references to this field.
What problem is it solving?
In Salesforce orgs using API version 46 or below, the TASK.WHAT_NAME field is sometimes included in the XML of layouts for which it isn't valid, leading to an Invalid field:TASK.WHAT_NAME error if you attempt to deploy this XML.
Since this issue was fixed by Salesforce in API version 47, the problem analyzer is only triggered when using API versions below this.
How does it work?
If you accept the suggested fix we'll remove that field from the XML and deploy the rest of the layout for you.