> Does Amazon have any policies against offering AGPv3 software as a service?
Each use of AGPLv3 licensed software has to be reviewed to ensure that the obligations of the license can be and will be met (and also screen for cases where it is known that the vendor of software does not prefer a company like Amazon import the software under a FOSS license). Today we use AGPLv3 licensed software internally, and include AGPLv3 licensed software in Amazon Linux (Ghostscript, in particular).
> Does Amazon contribute funding back to the software projects they offer as a service?
Yes, in varying ways. For example, it is not easy to provide "funding" for something like Apache Kafka. You need to have people working on the upstream.
> Does Amazon contribute code changes back to the software projects they modified when offering them as a service?
Yes, but not all changes are appropriate for upstream.
> But the (modified) source is available to consumers of the service either way, under the AGPL?
If Amazon made an AGPLv3 licensed program available to others over a network, it would have an obligation to provide to anyone that has access to that program the complete corresponding source.
Today, there aren't any services from Amazon that offer AGPLv3 licensed programs as a service. An example that may come to someone's mind is Grafana, but there is a partnership there, and AGPLv3 is not the binding license in that case.
In my personal opinion, AGPLv3 compliance is not difficult, so long as the licensor of the software is committed to community-oriented copyleft enforcement principles [1].
I think it would be awesome if Amazon could offer hosted AGPLv3 software, plus revenue share with the developers, code contributions to the original project and public forks containing non-upstreamable changes.
Does Amazon contribute funding back to the software projects they offer as a service?
Does Amazon contribute code changes back to the software projects they modified when offering them as a service?