Office Cache

link - docs.microsoft.com/en-us/office/dev/add-ins/testing/clear-cache

Location

"userprofile"\local settings\application data\assembly

 %localappdata% \ Microsoft\Office\16.0\Wef\ 
C:\Users\ "UserName" \AppData\Local\Microsoft\Office\16.0\Wef\ 

windows - %userprofile%\AppData\Local\Packages\Microsoft.Win32WebViewHost_cw5n1h2txyewy\AC\#!123\INetCache\

mac - /users/'devicename' / Library / Containers / com.Microsoft.OsfWebHost / Data

Clearing the WEF folder is not enough because the Office applications actually uses the browser to cache the manifest file and not the WEF folder.

link - stackoverflow.com/questions/48197843/remove-update-excel-add-in-sideloaded-via-shared-catalog

HTML files

<meta http-equiv="Cache-Control" 
                 "Pragma" 
                 "Expires"