The last time I read any updates on this, everyone on both sides of the legal process were trying to single out scapegoat individual software engineers and rake them over the coals. Did something change?
When the VW scandal broke, the US indicted seven senior executives. None of these seven were extradited to the US to stand trial [1].
The VW scandal was made public in 2015 [2] and involved cheating since 2009. Sentencing only two executives to jail a decade after their wrong doing made international news does not send a strong message.
[1] https://www.justice.gov/archives/opa/pr/former-ceo-volkswage...
Sending own citizens to foreign country is generally big deal and not something that is done.
One more mid level engineer involved in the scandal made the mistake of taking a vacation to Florida. He was arrested in the airport awaiting his flight home to Germany [2]. He was sentenced to 84 months in prison but was let out after serving half of that sentence [3].
[1] https://www.justice.gov/archives/opa/pr/former-ceo-volkswage...
[2] https://money.cnn.com/2017/03/17/news/companies/volkswagen-e...
[3] https://www.autonews.com/automakers/ex-vw-manager-schmidt-ge...
https://www.state.gov/wp-content/uploads/2019/02/10-201.9-Ge...
Article 16 (2) No German may be extradited to a foreign country. The law may provide otherwise for extraditions to a member state of the European Union or to an international court, provided that the rule of law is observed.
USA is not a member of European Union nor an international court.