Previously, the copyright notice was in the header of each file. However, this was untenable from a maintenance perspective: in the first few days of January every year, somebody would submit a patch touching every single file to update the copyright range.
Eventually, we made the policy: update the range only when the file is updated. However, this often was omitted, and reviewers would miss that it wasn’t changed as well.
So we moved to having the file docblock reference the COPYRIGHT.md file, and we can manage the date range from there.
In all other regards, however, it’s exactly the same scenario as it was under Zend Framework. Because we follow the BSD-3-Clause license, if you distribute Laminas code in any way, including copying for purposes of modification, you are required to provide a copyright reference in your code. This can be in your file’s docblock (e.g., “Some parts Copyright © 2019-2020 Laminas Foundation (https://getlaminas.org)”), or in your project’s copyright notices.