A revision in Aspose.Words is a change in one document node. A set of sequential revisions of the same type in adjacent document nodes forms a revision group. Similar revision groups are displayed in the “Reviewing Pane” of MS Word.
You can get the revision group by using Document.Revisions.Groups property and all revision of document using Document.Revisions property.
If you want to get the deleted text in group revision, you can get it by RevisionGroup.Text property and check deleted type using RevisionGroup.RevisionType.
You can also get the deleted text revision using Run.Text property when Run.IsDeleteRevision is true.
We suggest you please read the following articles.
Programmatically Access Revisions
Access Revision Group
Moreover, please check the following code example. Hope this helps you.
Document doc = new Document(MyDir + "input.docx");
foreach (Revision revision in doc.Revisions)
if (revision.ParentNode.NodeType == NodeType.Run && ((Run)revision.ParentNode).IsDeleteRevision)