The code for that plugin was updated at the same time as the others, but there was a compile warning/error that happened during the build process. I didn’t get that error/warning so I was only able to guess what would fix it. I (attempted to) fix it right away and have send the updated code to Epic, you’re now waiting for them to build and to publish it. I hope that this time it will build and publish successfully.
You should have the plugin downloaded and unzipped so that [project]/Plugins/LowEntryExtStdLib/LowEntryExtStdLib.uplugin exists. Then you should rightclick your project’s .uproject file and click on “Generate Visual Studio project files”. Then you should open the generated .sln file with Visual Studio and compile that project. You should then have the DLL for the project be build (check the output log). If this doesn’t happen, then I don’t know what’s going wrong, you might want to post this on the UE4 Answerhub as a bug report then, as you did all the right steps then as far as I know.