Per Bloomberg:

Elon Musk asked engineers from Tesla Inc., the electric-car maker he runs, to meet with product leaders at Twitter Inc., moving swiftly to make a mark on the company he’s about to take private, according to people familiar with the matter.

Earlier Thursday in Twitter’s San Francisco headquarters, product leaders showed Tesla engineers the company’s code, so they could assess and explain to Musk what the company needs, according to one of the people.

Twitter’s engineers can no longer make changes to code as of noon in San Francisco, the people said. That’s part of an effort to ensure that nothing about the product changes ahead of the deal closing, said the people, who declined to be named because the process isn’t public. Twitter enacted a similar freeze when the deal was first announced in April.