To indicate text is a variable name. Use for any variable names except those including "I" (uppercase i) and/or "l" (lowercase L); for these, {{var serif}} should be used to ensure a noticeable distinction
To display parameters as used in code (i.e. with triple braces), especially to indicate relationships between them. May be combined with {{para}} above
To display parameter values lightly bordered; replaces <code>...</code>, especially when value contains embedded or leading/trailing blanks; visualized here with middot (·) but can use ␠, ▯, or any character.
To indicate text is source code. To nest other templates within {{code}}, use <code>...</code>. {{codett}} differs only in styling: someMethod becomes Template:Codett
(Template:Thin space) To indicate deprecated source code in template documentation, articles on HTML specs, etc. The {{dc2}} variant uses strike-through (<blink>) while {{dcr}} uses red (<Template:Dcr>).
Template documentation