<dependency>
  <groupId>org.dmfs</groupId>
  <artifactId>optional</artifactId>
  <version>1.19</version>
</dependency>

implementation 'org.dmfs:optional:1.19'

implementation("org.dmfs:optional:1.19")

libraryDependencies += "org.dmfs" % "optional" % "1.19"

@Grapes(
  @Grab(group='org.dmfs', module='optional', version='1.19')
)

<dependency org="org.dmfs" name="optional" rev="1.19" />

[org.dmfs/optional "1.19"]

'org.dmfs:optional:jar:1.19'