What are the terms that Signal attaches to the binaries?
If unmodified binaries are redistributed, there is no trademark violation. It's nominative use, and simply not misleading the public because it's the genuine article. Any obstacle to redistribution must therefore come from the copyright licensing terms (if the binaries are available to the general public), or from an individual agreement with the original recipient of the binaries (so no direct free, public downloads even if the binaries are technically under an open-source license, and export compliance is a bit more difficult). Not sure which applies here, but it's not a trademark issue.
If unmodified binaries are redistributed, there is no trademark violation. It's nominative use, and simply not misleading the public because it's the genuine article. Any obstacle to redistribution must therefore come from the copyright licensing terms (if the binaries are available to the general public), or from an individual agreement with the original recipient of the binaries (so no direct free, public downloads even if the binaries are technically under an open-source license, and export compliance is a bit more difficult). Not sure which applies here, but it's not a trademark issue.