I try to install foreman on a plain Debian 9.1 strech minimal installation using the following steps:

wget https://apt.puppetlabs.com/puppetlabs-release-pc1-stretch.deb
dpkg -i puppetlabs-release-pc1-strech.deb

echo "deb http://deb.theforeman.org/ stretch nightly" > /etc/apt/sources.list.d/foreman.list
echo "deb http://deb.theforeman.org/ plugins nightly" >> /etc/apt/sources.list.d/foreman.list
wget q https://deb.theforeman.org/pubkey.gpg -O | apt-key add -

apt-get update && apt-get -y install foreman-installer

So far, so good, foreman-installer is installed. When running it though, it tries to install puppetserver, which cannot be found. AFAIK it has been renamed to puppetmaster.

This is the output:

--- snip ---
root@foreman:/tmp# foreman-installer
Execution of '/usr/bin/apt-get -q -y -o DPkg::Options::=--force-confold install puppetserver' returned 100: Reading package lists...
Building dependency tree...
Reading state information...
E: Unable to locate package puppetserver
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util/execution.rb:235:in `execute'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/provider/command.rb:23:in `execute'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/provider.rb:221:in `block in has_command'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/provider.rb:422:in `block in create_class_and_instance_method'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/provider/package/apt.rb:73:in `install'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/type/package.rb:88:in `block (3 levels) in <module:Puppet>'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/property.rb:487:in `set'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/property.rb:561:in `sync'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/transaction/resource_harness.rb:236:in `sync'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/transaction/resource_harness.rb:134:in `sync_if_needed'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/transaction/resource_harness.rb:80:in `perform_changes'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/transaction/resource_harness.rb:21:in `evaluate'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/transaction.rb:230:in `apply'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/transaction.rb:246:in `eval_resource'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/transaction.rb:163:in `call'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/transaction.rb:163:in `block (2 levels) in evaluate'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util.rb:507:in `block in thinmark'
/opt/puppetlabs/puppet/lib/ruby/2.1.0/benchmark.rb:294:in `realtime'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util.rb:506:in `thinmark'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/transaction.rb:163:in `block in evaluate'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/graph/relationship_graph.rb:118:in `traverse'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/transaction.rb:154:in `evaluate'
/usr/lib/ruby/vendor_ruby/kafo/modules/kafo_configure/lib/puppet/parser/functions/add_progress.rb:30:in `evaluate_with_trigger'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/resource/catalog.rb:222:in `block in apply'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util/log.rb:155:in `with_destination'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/transaction/report.rb:142:in `as_logging_destination'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/resource/catalog.rb:221:in `apply'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/configurer.rb:171:in `block in apply_catalog'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util.rb:224:in `block in benchmark'
/opt/puppetlabs/puppet/lib/ruby/2.1.0/benchmark.rb:294:in `realtime'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util.rb:223:in `benchmark'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/configurer.rb:170:in `apply_catalog'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/configurer.rb:343:in `run_internal'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/configurer.rb:221:in `block in run'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/context.rb:65:in `override'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet.rb:306:in `override'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/configurer.rb:195:in `run'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/application/apply.rb:350:in `apply_catalog'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/application/apply.rb:274:in `block in main'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/context.rb:65:in `override'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet.rb:306:in `override'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/application/apply.rb:225:in `main'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/application/apply.rb:170:in `run_command'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/application.rb:358:in `block in run'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util.rb:662:in `exit_on_fail'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/application.rb:358:in `run'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util/command_line.rb:132:in `run'
/opt/puppetlabs/puppet/lib/ruby/vendor_ruby/puppet/util/command_line.rb:72:in `execute'
/opt/puppetlabs/puppet/bin/puppet:5:in `<main>'
/Stage[main]/Puppet::Server::Install/Package[puppetserver]/ensure: change from purged to present failed: Execution of '/usr/bin/apt-get -q -y -o DPkg::Options::=--force-confold install puppetserver' returned 100: Reading package lists...
Building dependency tree...
Reading state information...
E: Unable to locate package puppetserver
Installing Done [100%] [....................................................................]
Something went wrong! Check the log for ERROR-level output * Foreman is running at https://foreman.esxi.d-herrmann.de
Initial credentials are admin / eMCUC3Jmy49Giybt * Foreman Proxy is running at https://foreman.esxi.d-herrmann.de:8443 * Puppetmaster is running at port 8140
The full log is at /var/log/foreman-installer/foreman.log
--- snap ---

When verifying this, I can see that there indeed is no such packet, but there is a puppetmaster packet:

--- snip ---
root@foreman:/tmp# apt-cache search puppetsever
root@foreman:/tmp# apt-cache search puppetmaster
puppetmaster - configuration management system, master service - transitional package
puppetmaster-passenger - configuration management system, scalable master service - transitional package
trocla - generate and store passwords and certificates on a central server
foreman - Systems management web interface
--- snap ---

I will attach the full log