What is the unicode variation selector

Question

I was wondering. What is the unicode Variation Selectors U-FE00 to U-FE0F used for.

Example: ︀︁︂︂ 

Answer 1

The Variation Selectors range was introduced with version 3.2 of the Unicode Standard, and is located in Plane 0, the Basic Multilingual Plane. Further selectors can be found in the Variation Selectors Supplement range.

Most Unicode characters can be represented by a wide variety of glyphs, and in rich text a particular glyph can be indicated by choosing a particular font or style. This mechanism is not available in plain text, and so variation selectors have been introduced as a way of indicating that the glyphs applicable to a particular character should be changed or restricted. The base character is followed by the variation selector, the combination being called a variation sequence. This is not intended to be general-purpose mechanism, and the only permitted variation sequences are those defined in the Standardized Variants file, which forms part of the Unicode Character Database.

From http://www.alanwood.net/unicode/variation_selectors.html