Reporting is based on several construction permit applications that Tesla submitted for the Fremont factory over the last week including an application submitted on April 3 showing Tesla is installing a "new conveyance platform for Model Y production". Tesla also submitted several permit applications to recommission its south paint shop as well as applications for a general assembly line that it has been referring to as “GA4.5.”
https://electrek.co/2020/04/06/tesla-improvements-fremont-factory-model-y-production-capacity/
https://electrek.co/2020/04/06/tesla-improvements-fremont-factory-model-y-production-capacity/