Copy and paste your arcgis rest api endpoint URL next to 'let's go' button, then click 'enter' key or 'let's go' button
Folder
https://transparentgov.net/json2tree/esri/server/folder.html
Layer
https://transparentgov.net/json2tree/esri/server/searchLayer.html?url=&org=&cross=default&timeout=10000&filter_by=
MapServer
https://transparentgov.net/json2tree/esri/server/searchMapServer.html?url=&org=&cross=default&timeout=10000&filter_by=
How to use
https://transparentgov.net/cleargov1/1149/how-to-explore-arcgis-rest-api-endpoint-army-corps-engineers