Hello. I'm trying to learn and understand VPP. But I don't have .am, .ac files. Why?
https://s3-docs.fd.io/vpp/23.02/developer/plugindoc/sample_plugin_doc.html

How to create a new plugin

To create a new plugin based on the sample plugin, copy and rename the sample plugin directory and automake config.
cp -r src/examples/sample-plugin/sample src/plugins/newplugin cp src/examples/sample-plugin/sample.am src/plugins/newplugin.am
Add the following entry to the plugins section of src/configure.ac.
PLUGIN_ENABLED(newplugin)
Add the following entry to the plugins section of src/plugins/Makefile.am
if ENABLE_NEWPLUGIN include newplugin.am endif