Support for AlgoSigner by the Algorand Foundation is ending on March 31st and the extension will be unpublished from the Chrome Store. This should not delete the extension if it is installed through the store but neither the extension or code base will be updated or supported.
Refer to the Algorand website for a list of alternative providers (Ecosystem Tools & Projects | Algorand Developer Portal). The Algorand Foundation also providers a list of wallet security best practices (A Guide to Wallet Security and Best Practices).
Existing users should migrate to a different wallet immediately. There is no way to export a mnemonic from AlgoSigner. If you did not write it down when creating an account you should migrate to another account before March 31st or rekey your account to an account you do have the secret for.
For developers, the Github repo for the project will migrate to the Algorand Foundation on March 31st.
Foundation press release (AlgoSigner Support Ends on March 31st, 2023 | Algorand Foundation News)
Q: Does this have anything to do with the MyAlgo wallet breach?
A: No, this is a planned phasing out of AlgoSigner. There is no known security issue with the wallet.
Q: Can I rekey my account?
A: Yes, you can, several guides are available recently depending on your new wallet.
Q: Are there are any more releases planned?
A: There are no more planned releases to the Chrome Store. There is final code only release (1.11.0) in the Github repository with the last developed features.
Q: Is the code Manifest v3 ready?
A: No. There will be a branch containing all the changes towards supporting v3, but it should not be considered tested or production ready.