drupal/core/modules/tracker/tracker.routing.yml

tracker.page:
  path: '/activity'
  defaults:
    _controller: '\Drupal\tracker\Controller\TrackerController::buildContent'
    _title: 'Recent content'
  requirements:
    _permission: 'access content'

tracker.users_recent_content:
  path: '/activity/{user}'
  defaults:
    _controller: '\Drupal\tracker\Controller\TrackerController::buildContent'
    _title: 'My recent content'
  requirements:
    _permission: 'access content'
    _custom_access: '\Drupal\tracker\Controller\TrackerController::checkAccess'
    user: \d+

tracker.user_tab:
  path: '/user/{user}/activity'
  defaults:
    _controller: '\Drupal\tracker\Controller\TrackerController::buildContent'
    _title_callback: '\Drupal\tracker\Controller\TrackerController::getTitle'
  requirements:
    _permission: 'access content'
    _entity_access: 'user.view'
    user: \d+