The Mercurial Export Diff dialog box enables you to export all the diffs for modified files within a given changeset.
You can access the Export Diff dialog by choosing Versioning > Export Diff from the main menu.
Export from: Select a revision from the drop-down field. Revisions are displayed containing revision numbers and corresponding changeset IDs in parentheses. Revisions are listed according to date (i.e., the most current revision is displayed by default).
Output File: Specify the name and location of the output file that will be generated from performing the export. Click Browse to open an explorer allowing you to navigate to a specific location on your computer.