What is a "link template" in a token?
Link templates are defined in the entity class. For webform_submission:

 *   links = {
 *     "canonical" = "/admin/structure/webform/manage/{webform}/submission/{webform_submission}",
 *     "access-denied" = "/admin/structure/webform/manage/{webform}/submission/{webform_submission}/access-denied",
 *     "table" = "/admin/structure/webform/manage/{webform}/submission/{webform_submission}/table",
 *     "text" = "/admin/structure/webform/manage/{webform}/submission/{webform_submission}/text",
 *     "yaml" = "/admin/structure/webform/manage/{webform}/submission/{webform_submission}/yaml",
 *     "edit-form" = "/admin/structure/webform/manage/{webform}/submission/{webform_submission}/edit",
 *     "notes-form" = "/admin/structure/webform/manage/{webform}/submission/{webform_submission}/notes",
 *     "resend-form" = "/admin/structure/webform/manage/{webform}/submission/{webform_submission}/resend",
 *     "duplicate-form" = "/admin/structure/webform/manage/{webform}/submission/{webform_submission}/duplicate",
 *     "delete-form" = "/admin/structure/webform/manage/{webform}/submission/{webform_submission}/delete",
 *     "collection" = "/admin/structure/webform/submissions/manage/list"
 *   },


Source: https://git.drupalcode.org/project/webform/blob/8.x-5.x/src/Entity/WebformSubmission.php