The keyword explicitly lists both Opentype and Truetype because the arial.ttf from version 7.01 is a hybrid. How can one file be both?
Thus, Arialnormal Opentype Truetype correctly identifies that the font uses OpenTypE layout logic on TrueType glyph data. Most font managers today will list it under "OpenType (TrueType outlines)."
This is a common hybrid:
Why “OpenType TrueType” in metadata?
Microsoft and Adobe defined OpenType as a wrapper that can contain either: arialnormal opentype truetype version 701 western top
So “OpenType TrueType” is correct but confusing to end users. It simply means: OpenType tables + TrueType glyphs.
OpenType, launched in 1996, is a superset of TrueType. It can contain either TrueType outlines (quadratic curves) or PostScript/CFF outlines (cubic Bézier curves). The key advantage of OpenType is its support for:
So how can a font be both OpenType and TrueType? The "Arialnormal Opentype Truetype Version 701 Western Top" font is technically an OpenType font with TrueType outlines. In practical terms: The keyword explicitly lists both Opentype and Truetype
Version 701 specifically refers to a build of Microsoft’s core fonts. This version was distributed extensively with Windows Vista, Windows 7, and early versions of Windows 10. It is a transitional release that included improved hinting for LCD screens (ClearType) and updated character maps.
You will often see this font listed as Arial (Western). This refers to the Code Page support.
While other versions exist (Greek, Cyrillic, Arabic, Hebrew), the Western build is the most widely distributed font file on the planet. Why “OpenType TrueType” in metadata
The word "Top" at the end of the keyword is the most ambiguous but crucial component. In font metadata, "Top" can signify several things:
The term "Western" in the font keyword refers to the character set or script tag built into the font.
Fonts can support multiple script systems:
When a font file lists "Western" prominently in its metadata (often in the name table ID 13 or as part of the OS/2 table’s code page range), it means that this specific font file only contains Western Latin glyphs. It is a subset font.