The data for the widgets is stored in the CMS_Document
table under the column DocumentPageBuilderWidgets
. It looks like it is stored in json format.
So you can search for pages that contain a certain string by doing a query like this:
select * from dbo.CMS_Document cd
where cd.DocumentPageBuilderWidgets like '%Lorem Ipsum%'
If you want more detail than that, like what widget contains that string, you will have to parse the data.