The NARs in src/test/resources/extensions came from building the source code found in nifi-example-nars-source.zip.

If you need to make a change to these NARs, perform the following steps:

1) Copy nifi-example-nars-source.zip somewhere and extract it
2) Modify code and build
3) Replace NARs in src/test/resources/extensions with results from build in step 2
4) Create a zip archive of the modified source code
5) Replace nifi-example-nars-source.zip with the new zip archive