Few IGB Apps are not showing in App Manager when added

When going through the documentation (https://wiki.bioviz.org/confluence/display/igbdevelopers/Hello+World+IGB+App) to create a new plugin IGB App, came across this sample IGB app https://bitbucket.org/lorainelab/hello-world-igb-app/src/master/ which isn't working as expected now, same case with ncbi-primer, https://bitbucket.org/lorainelab/ncbi-primer/src/master/ both when added as repositories in Manage repositories tab isn't getting added as a new App in the App Manager.

Steps to reproduce:

1. Clone a copy of the Hello World App source code from Bitbucket - https://bitbucket.org/lorainelab/hello-world-igb-app
2. Build the app using mvn clean install command, it generates a target folder.
3. Start IGB
4. Select Tools > Open App Manager
5. Click Manage Repositories... button (opens Plug-in Repositories tab in Preferences window)
6. Click Add... button (opens Plugin Repository dialog)
7. Enter a name for your repository (can be anything)
8. Click Choose local folder button
9. Select the "target" folder in your igb-app-hello-world project folder.
10. Once you add "target" as a new local App repository, you should see the Hello World App added as a new App in the IGB App Manager window but this isn't working as expected.