Sources for both fonts are:

Roboto
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Roboto is using the same license as the library - Apache 2.0 (not repeated here, see top level).
https://fonts.google.com/specimen/Roboto

Open Sans
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Open Sans is using OFL, see the file in this directory.
https://fonts.google.com/specimen/Open+Sans

Please read the full license text (OFL.txt) to understand the permissions,
restrictions and requirements for usage, redistribution, and modification.

You can use them in your products & projects – print or digital,
commercial or otherwise.

This isn't legal advice, please consider consulting a lawyer and see the full
license for all details.