lookup> .u8hdr

.U8HDR·File Extension

U8HDR Other — A .u8hdr file is a U8HDR Other. It is a file format typically read and written by specialized applications.

Othermessage/global-headers

Quick facts

Extension.u8hdr

File typeU8HDR Other

MIME typemessage/global-headers

CategoryOther

Charset—

Compressible—

What is .u8hdr

What is a .u8hdr file?

A .u8hdr file is a U8HDR Other. It is a file format typically read and written by specialized applications.

In the mime-db registry it maps to message/global-headers. When serving .u8hdr over HTTP, set the Content-Type header as shown in Developer info below.

Related entities: it maps to message/global-headers — and is delivered over HTTP via the Content-Type header.

How to open .u8hdr files

Use VS Code or xxd to open and edit .u8hdr files.
Any text editor (Notepad, VS Code) can inspect the raw content as text.

Developer info

When served over HTTP, responses should set the following header:

Content-Type: message/global-headers

Common software that reads/writes .u8hdr:

VS Codexxd7-Zip

Relation chain

.u8hdrextension of

format

U8HDR Otherserved as

mime type

message/global-headerssent via header

http header

Related extensions

Related MIME types

message/global-headers

.u8hdr

Common uses

Application-specific data

How to edit .u8hdr files

Open the file with VS Code, make your changes and save.
Most editors preserve the original formatting and encoding — avoid changing the charset.

How to create .u8hdr files

Create a new file and save it with the .u8hdr extension, or export this format from VS Code.

Frequently asked questions

What programs can open .u8hdr files?

Common options include VS Code, xxd, 7-Zip. You can also open many of these files with built-in viewers or a browser.

How do I create a .u8hdr file?

Create a new file in any text editor or the app that owns the format and save it with the .u8hdr extension.

What is the relationship between .u8hdr and the message/global-headers MIME type?

message/global-headers is the media type identifier used for .u8hdr files during network transfer (for example in the HTTP Content-Type header).

Sources & standards

Updated 2026-09-13

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