Microsoft is developing a new Edge mode, allowing users to use the same rendering engine with the classic Edge visit the site to continue using the legacy Web applications.
Chromium is based on Microsoft Edge, users can enable the feature "Internet Explorer mode", which mimic the functions of the browser Internet Explorer 11. In this mode you can use the legacy Web applications. Enabling Internet Explorer mode, Internet Explorer icon will appear in the address bar, and visited website would think that running is Internet Explorer 11.
Similarly, Microsoft Edge Dev and Canary version adds a "Open site in Edge mode," the new options. Although not yet announced any official information on this feature, but it is likely to cause the browser to imitate the classic version of the Edge.
To use this feature, the need to edge: // flags / # edge-internet-explorer-integration "Enable IE Integration" (Enable IE Integration) flag is set to "IE mode '' (IE Mode).
Once configured, users can use the "--ie-mode-test" command line parameter to start the new Microsoft Edge program to enable Internet Explorer mode function. With this feature enabled, Options -> More tools under the "Open site in Edge mode" option becomes available.
Source: bleepingcomputer