If the Stellar core was forked and changed, and some software like digital wallet was built on top of the resulting private blockchain, what notices should be mandatorily included with this software (on GUI and elsewhere)? According to Apache 2.0 license, section 4 c) and d):
You must retain, in the Source form of any Derivative Works that You distribute, all copyright, patent, trademark, and attribution notices from the Source form of the Work, excluding those notices that do not pertain to any part of the Derivative Works;
If the Work includes a "NOTICE" text file as part of its distribution, then any Derivative Works that You distribute must include a readable copy of the attribution notices contained within such NOTICE file, excluding those notices that do not pertain to any part of the Derivative Works, in at least one of the following places: within a NOTICE text file distributed as part of the Derivative Works; within the Source form or documentation, if provided along with the Derivative Works; or, within a display generated by the Derivative Works, if and wherever such third-party notices normally appear. The contents of the NOTICE file are for informational purposes only and do not modify the License. You may add Your own attribution notices within Derivative Works that You distribute, alongside or as an addendum to the NOTICE text from the Work, provided that such additional attribution notices cannot be construed as modifying the License.
I did not find the NOTICE file in the source repository, and no trademarks or patents whatsoever. Does this mean the proprietary software can be built on top of the Stellar core without any notices or did I get something wrong here?