Microsoft released an Indexer Diagnostics tool to help users troubleshoot and, in some cases, fix Windows Search problems they might experience on their Windows 10 devices. The tool, which is still in Beta, does this by allowing you to detect potential issues affecting the Search Indexer service by making it possible to check if your files are indexed and what paths are indexed. Microsoft will continue adding functionality to the app in the future, with the end goal of helping Windows 10 customers experiencing search issues to fix them easier or to report them to the development team.
Source: https://www.bleepingcomputer.com/news/microsoft/microsofts-indexer-diagnostics-helps-troubleshoot-windows-search/