Tamil is a Unicode block containing characters for the Tamil, and Saurashtra languages of Tamil Nadu India, Sri Lanka, Singapore, and Malaysia. In its original incarnation, the code points U+0B82..U+0BCD were a direct copy of the Tamil characters A2-ED from the 1988 ISCII standard. The Devanagari, Bengali, Gurmukhi, Gujarati, Oriya, Telugu, Kannada, and Malayalam blocks were similarly all based on their ISCII encodings.
The following Unicode-related documents record the purpose and process of defining specific characters in the Tamil block:
The UTC approves changing the general category type of U+0B83 TAMIL SIGN VISARGA from Mn to Lo.
Make script extension changes in version 11.0 as documented in section 6B, pages 6-9 of L2/18-039.