As a plugin developer you can use this plugin as dependency of your plugin by adding a dependency tag to your POM.
To add the latest version of this plugin as a maven dependency, use the following:
<dependency> <groupId>io.jenkins.plugins</groupId> <artifactId>flatpickr-api</artifactId> <version>4.6.13-5.v534d8025a_a_59</version> </dependency>