TYPO3 v8 has reached its end-of-life March 31st, 2020 and is not maintained by the community anymore.
You can order Extended Long Term Support (ELTS) here: TYPO3 ELTS.
Namespaces and class names of user files¶
The namespace and class names of user files follow the same rules as class names of the TYPO3 Core files do.
The namespace declaration of each user file should show where the file
belongs inside its extension. The namespace starts with
"Vendor\MyNamespace\", where "Vendor" is your vendor name and
"MyNamespace" is the extension name in UpperCamelCase. Then follows the
name of the subfolder of
Classes/, in which the file is located
(if any). E.g. the file
with the class
AliasesController is in the namespace
User files with these class names are commonly found in the
typo3conf/ext/ directory. Optionally these files can be
installed to the
typo3/ext/ directory to be shared by many