Updated 20 January, 2020
This page lists characters in the following Unicode block and provides information about them.
This is not authoritative, peer-reviewed information – these are just notes I have gathered and copied from various places.
For further information related to scripts, see the Script links pages.
Find
If you click on any red example text, you will see at the bottom right of the page a list of the characters that make up the example. Click on the 
icon to toggle the large characters between font glyphs and graphics.
Read more about how to use this page.
To find a character by codepoint, type #char0000 at the end of the URL in the address bar, where 0000 is a four-figure hex codepoint number, all in uppercase. Or type the character or the hex number in the Find control just above.
To view this page as intended, you need appropriate fonts. For transcriptions I recommend the excellent and free Doulos SIL font. The large character in the box will not be rendered unless a system font has a glyph for it. (If there is no glyph and you want to see what it looks like, click on See in UniView.)
Information about languages that use these characters is taken from the list maintained for the Character Use app. The list is not exhaustive.
The transliteration scheme was developed by myself, and, where possible, uses symbols that represent sounds typically associated with their equivalents, rather than the sometimes fairly arbitrary selection of diacritics found in other systems. Of course, the complexities of mapping graphemes to sounds means that this is far from a real phonetic transcription, but the process is reversible (unlike most transcriptions).
References are indicated by superscript characters. Wherever possible, those contain direct links to the source material. When such a pointer is alongside an arrow → it means that it's worth following the link for the additional information it provides. Digits refer to the main sources, which are listed at the bottom of a set of notes.
When you are using UniView and you turn on Show notes, UniView will pull in information about characters from this page.