This not Work
$themeslug_loader->add( 'WPTRT\\Customize\\Section\\', get_theme_file_path( 'path/to/customize-section-button/src' ) );
$loader->add( $prefix, $path );
$prefix - This should be the namespace of the project.
this is work and load the classes
$themeslug_loader->add( 'WPTRT\\Customize\\', get_theme_file_path( 'path/to/customize-section-button/src' ) );
This not Work
$themeslug_loader->add( 'WPTRT\\Customize\\Section\\', get_theme_file_path( 'path/to/customize-section-button/src' ) );$loader->add( $prefix, $path );$prefix- This should be the namespace of the project.this is work and load the classes
$themeslug_loader->add( 'WPTRT\\Customize\\', get_theme_file_path( 'path/to/customize-section-button/src' ) );