XTG File

What are XTG files and how to open them

Are you having problems opening an XTG file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your XTG files.

What is an XTG file?

XTG files have multiple uses, and EXtensible TreeGraph Format is one of them. Read more about the other uses further down the page.

EXtensible TreeGraph Format

XTG, short for extensible TreeGraph format, is a type of XML document utilized by TreeGraph 2 to read and write data.

TreeGraph 2 is an open-source application used for creating and editing phylogenetic trees, which allows annotations to be attached to nodes or branches. It also supports various graphical formats and editing operations. Many types of data, including tables and BayesTraits outputs, can be imported into a tree format. An important characteristic of this is the ability to compare and combine different topologies by interactive means.

How to open XTG files

We have identified one XTG opener that is compatible with this specific type of XTG file.

Programs that open EXtensible TreeGraph Format files

Last updated: August 14, 2026

All known file formats using extension .XTG

While EXtensible TreeGraph Format is a popular type of XTG-file, we know of 2 different uses of the .XTG file extension. Different software may use files with the same extension for different types of data.

QuarkXPress Tags

QuarkXPress Tags (.xtg) is a plain-text format used by QuarkXPress to export or save textual content with its formatting embedded via special codes. It lets users transfer styled and styled-text content between QuarkXPress projects or between QuarkXPress and other applications while preserving attributes like font, style sheet, color, paragraph rules, and indexing.

This format is produced by QuarkXPress when choosing the Save Text command or exporting texts with the XPress Tags filter. Users or external programs can generate .xtg files by writing text files with embedded XPress-Tags codes. When QuarkXPress imports a .xtg file, it interprets those codes to apply formatting; if the codes are not interpreted, the coded text appears unformatted.

In the file, codes are enclosed in angle brackets (< >). Character attributes include tags such as <B> for bold, <I> for italic, <U> for underline; paragraph formatting tags control alignment, hyphenation, rules above or below, etc. Indexing tags include <XI,Tag Info> for index markers, <XO> and <XC,Tag Info> to mark and end ranges. Files typically begin with a version tag and an encoding tag like <v21.00><e8>.

Some internal identifiers appear at fixed positions in .xtg files. For example, at offset 0 the bytes 0x3C76 (ASCII ".v") appear, followed by other specific byte sequences; the strings PRESS, BEEN, and IONS occur within the data, helping identify the format.

XTG opener for Windows

We have identified one XTG opener that is compatible with this specific type of XTG file.

Various apps that use files with this extension

These apps are known to open certain types of XTG files. Remember, different programs may use XTG files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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