Presenter at the last in-person MS Ignite (so, 2019?). He mentioned to the audience they rewrote Notepad.exe and showed the memory usage of NP++ and Notepad.exe

Presenter at the last in-person MS Ignite (so, 2019?). He mentioned to the audience they rewrote Notepad.exe and showed the memory usage of NP++ and Notepad.exe while opening a 10GB CSV. But if you're saying it's not included in Windows 10 it might be a sysinternals branch.