Typo does not access or store your code at all. It accesses the metadata only to generate insights for Dev Analytics.
For Code Analysis, we do have a read access to analyse the code but we do not save your entire code anywhere in our systems. The analysis is run on a temporary storage and only the code snipped having the issue is saved to highlight & suggest relevant code fixes.
The same is clearly highlighted on the permissions screen as well that is visible to you as the first step when you onboard on Typo.