Could this be the "pipeline"?
Under this area maybe?
https:?//www.tcenergy.com/operations/maps/
https://www.tcenergy.com/siteassets/pdfs/natural-gas/north-baja-pipeline-system/transcanada-north-baja-pipeline-map.pdf
https://www.hartenergy.com/exclusives/north-baja-pipeline-delivers-gas-and-mexico-us-3503