Freeplane Nix Packages not working

The Freeplane package in search.nixos.org isn’t working it seems. I added the package to configuration.nix but the following is the error I am getting:

$ freeplane
Picked up _JAVA_OPTIONS: -Dawt.useSystemAAFontSettings=on
WARNING: package sun.swing.shell not in java.desktop
WARNING: A terminally deprecated method in java.lang.System has been called
WARNING: System::setSecurityManager has been called by org.freeplane.launcher.Launcher (file:/nix/store/n51zgy80kagvr1515b29w8fxmg7xjr42-freeplane-1.11.14/share/freeplane/freeplanelauncher.jar)
WARNING: Please consider reporting this to the maintainers of org.freeplane.launcher.Launcher
WARNING: System::setSecurityManager will be removed in a future release
Knopflerfish OSGi framework launcher, version <unknown>
Copyright 2003-2020 Knopflerfish. All Rights Reserved.
See http://www.knopflerfish.org for more information.

Created Framework: org.knopflerfish.framework, version=8.0.11.
java.io.FileNotFoundException: /nix/store/n51zgy80kagvr1515b29w8fxmg7xjr42-freeplane-1.11.14/share/freeplane/core/org.freeplane.core/META-INF/MANIFEST.MF (No such file or directory)
	at java.base/java.io.FileInputStream.open0(Native Method)
	at java.base/java.io.FileInputStream.open(FileInputStream.java:216)
	at java.base/java.io.FileInputStream.<init>(FileInputStream.java:157)
	at org.knopflerfish.framework.bundlestorage.file.Archive.downloadArchive(Archive.java:226)
	at org.knopflerfish.framework.bundlestorage.file.BundleArchiveImpl.<init>(BundleArchiveImpl.java:134)
	at org.knopflerfish.framework.bundlestorage.file.BundleStorageImpl.insertBundleJar(BundleStorageImpl.java:219)
	at org.knopflerfish.framework.Bundles.install0(Bundles.java:161)
	at org.knopflerfish.framework.SecurePermissionOps$14.run(SecurePermissionOps.java:737)
	at org.knopflerfish.framework.SecurePermissionOps$14.run(SecurePermissionOps.java:733)
	at java.base/java.security.AccessController.doPrivileged(AccessController.java:569)
	at org.knopflerfish.framework.SecurePermissionOps.callInstall0(SecurePermissionOps.java:732)
	at org.knopflerfish.framework.Bundles.install(Bundles.java:118)
	at org.knopflerfish.framework.BundleContextImpl.installBundle(BundleContextImpl.java:125)
	at org.knopflerfish.framework.Main.handleArgs(Main.java:549)
	at org.knopflerfish.framework.Main.start(Main.java:224)
	at org.freeplane.launcher.Launcher.startFramework(Launcher.java:335)
	at org.freeplane.launcher.Launcher.launchWithoutUICheck(Launcher.java:303)
	at org.freeplane.launcher.Launcher.main(Launcher.java:88)
Error: Command "-istart org.freeplane.core" failed, Failed to install bundle: java.io.FileNotFoundException: /nix/store/n51zgy80kagvr1515b29w8fxmg7xjr42-freeplane-1.11.14/share/freeplane/core/org.freeplane.core/META-INF/MANIFEST.MF (No such file or directory)

Is this an issue with the nix package or an issue with freeplane?

Smells like a packaging bug, create an issue in the Nixpkgs issue tracker and ping the maintainers. If nobody answers in a week or so, please notify someone (i.e. me) so that the package can be marked as broken to reflect its actual state or create a PR for this yourself if you want to.