Very often I see jars with lambdas not obfuscated, so I decided to create a jar of my own to exploit that and get a few real method names.
When a method has a lamdba, the compiled class file adds a private static synthetic method called something like lambda$main$0 where main is the method calling the lambda.
The actual call to the lambda is instead replaced with an invokedynamic which calls the bootstrap method.
For lambdas it is LambdaMetaFactory.metafactory. That bootstrap method takes a MethodHandle which contains the lambda name.