Types of files that cannot be added to a list or library - one drive - sharepoint online

here are certain types of files that you cannot upload to a SharePoint list or a library. By default, SharePoint blocks certain file types.

For example, if .asp is on the list of blocked file extensions, a file called "newpage.asp" is blocked. Variations of a file extension are also blocked. The following list shows different ways of representing the same file, all of which are blocked if the .hta extension is on the list of blocked file extensions.

• filename.hta
• filename.hta.
• filename.hta.{3050F4D8-98B5-11CF-BB82-00AA00BDCE0B}
• filename.hta::$DATA

The list of files that is blocked for SharePoint Online is different from the list of files that is blocked for on-premises deployments of SharePoint Foundation or SharePoint Server.

https://support.office.com/en-nz/article/Types-of-files-that-cannot-be-added-to-a-list-or-library-30be234d-e551-4c2a-8de8-f8546ffbf5b3?ui=en-US&rs=en-NZ&ad=NZ

Blocked file types for SharePoint Online

The list of blocked file types cannot be changed for a SharePoint Online site.

File extension	File type
.ashx	ASP.NET Web handler file. Web handlers are software modules that handle raw HTTP requests received by ASP.NET.
.asmx	ASP.NET Web Services source file
.json	JavaScript Object Notation file
.soap	Simple Object Access Protocol file
.svc	Windows Communication Foundation (WCF) service file
.xamlx	Visual Studio Workflow service file