diff --git a/doc/04-schema.md b/doc/04-schema.md
index f1859ea95..05149d331 100644
--- a/doc/04-schema.md
+++ b/doc/04-schema.md
@@ -401,19 +401,19 @@ Example:
 
 #### require
 
-Lists packages required by this package. The package will not be installed
+Map of packages required by this package. The package will not be installed
 unless those requirements can be met.
 
 #### require-dev <span>([root-only](04-schema.md#root-package))</span>
 
-Lists packages required for developing this package, or running
+Map of packages required for developing this package, or running
 tests, etc. The dev requirements of the root package are installed by default.
 Both `install` or `update` support the `--no-dev` option that prevents dev
 dependencies from being installed.
 
 #### conflict
 
-Lists packages that conflict with this version of this package. They
+Map of packages that conflict with this version of this package. They
 will not be allowed to be installed together with your package.
 
 Note that when specifying ranges like `<1.0 >=1.1` in a `conflict` link,
@@ -423,7 +423,7 @@ probably want to go for `<1.0 || >=1.1` in this case.
 
 #### replace
 
-Lists packages that are replaced by this package. This allows you to fork a
+Map of packages that are replaced by this package. This allows you to fork a
 package, publish it under a different name with its own version numbers, while
 packages requiring the original package continue to work with your fork because
 it replaces the original package.
@@ -441,10 +441,12 @@ that exact version, and not any other version, which would be incorrect.
 
 #### provide
 
-List of other packages that are provided by this package. This is mostly
+Map of packages that are provided by this package. This is mostly
 useful for implementations of common interfaces. A package could depend on
-some virtual `logger-implementation` package, any library that implements
-this logger interface would list it in `provide`.
+some virtual package e.g. `psr/logger-implementation`, any library that implements
+this logger interface would list it in `provide`. Implementors can then
+be [found on Packagist.org](https://packagist.org/providers/psr/log-implementation).
+
 Using `provide` with the name of an actual package rather than a virtual one
 implies that the code of that package is also shipped, in which case `replace`
 is generally a better choice. A common convention for packages providing an