Module Anatomy

[A-Z]+[A-Za-z0-9]{1,}_[A-Z]+[A-Z0-9a-z]{1,}

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Store:etc/config.xsd">
    <default>
        <pocketcoffee_skeleton>
            <general>
                <enabled>1</enabled>
                <min_rest_days>4</min_rest_days>
            </general>
        </pocketcoffee_skeleton>
    </default>
</config>

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:App/etc/routes.xsd">
    <router id="standard">
        <route id="pcskeleton" frontName="pcskeleton">
            <module name="PocketCoffee_Skeleton"/>
        </route>
    </router>
</config>

<?php
declare(strict_types=1);

namespace PocketCoffee\Skeleton\Controller\Index;

use Magento\Framework\App\Action\HttpGetActionInterface;
use Magento\Framework\App\Config\ScopeConfigInterface;
use Magento\Framework\Controller\Result\Raw;
use Magento\Framework\Controller\Result\RawFactory;
use Magento\Store\Model\ScopeInterface;

/**
 * GET /pcskeleton/index/index
 */
class Index implements HttpGetActionInterface
{
    private const XML_PATH_MIN_REST_DAYS = 'pocketcoffee_skeleton/general/min_rest_days';

    /**
     * @param RawFactory $rawFactory
     * @param ScopeConfigInterface $scopeConfig
     */
    public function __construct(
        private readonly RawFactory $rawFactory,
        private readonly ScopeConfigInterface $scopeConfig
    ) {
    }

    /**
     * @inheritDoc
     */
    public function execute(): Raw
    {
        $days = (int) $this->scopeConfig->getValue(self::XML_PATH_MIN_REST_DAYS, ScopeInterface::SCOPE_STORE);

        return $this->rawFactory->create()->setContents(
            sprintf('Pocket Coffee beans rest at least %d days after roasting.', $days)
        );
    }
}

<?php
declare(strict_types=1);

namespace PocketCoffee\Skeleton\Setup\Patch\Data;

use Magento\Framework\Setup\ModuleDataSetupInterface;
use Magento\Framework\Setup\Patch\DataPatchInterface;

/**
 * Runs once per database: setup:upgrade records it in the patch_list table.
 */
class RecordSkeletonInstall implements DataPatchInterface
{
    /**
     * @param ModuleDataSetupInterface $moduleDataSetup
     */
    public function __construct(private readonly ModuleDataSetupInterface $moduleDataSetup)
    {
    }

    /**
     * @inheritDoc
     */
    public function apply(): self
    {
        $connection = $this->moduleDataSetup->getConnection();
        $connection->startSetup();
        $connection->insertOnDuplicate(
            $this->moduleDataSetup->getTable('core_config_data'),
            [
                'scope' => 'default',
                'scope_id' => 0,
                'path' => 'pocketcoffee_skeleton/general/seeded',
                'value' => '1',
            ],
            ['value']
        );
        $connection->endSetup();

        return $this;
    }

    /**
     * @inheritDoc
     */
    public static function getDependencies(): array
    {
        return [];
    }

    /**
     * @inheritDoc
     */
    public function getAliases(): array
    {
        return [];
    }
}

"Roast date","Roast date"
"Beans rest at least %1 days after roasting.","Beans rest at least %1 days after roasting."

$ bin/magento module:status PocketCoffee_Skeleton
PocketCoffee_Skeleton :  Module is disabled

$ bin/magento module:enable PocketCoffee_Skeleton
The following modules have been enabled:
- PocketCoffee_Skeleton

To make sure that the enabled modules are properly registered, run 'setup:upgrade'.
Cache cleared successfully.
Generated classes cleared successfully. Please run the 'setup:di:compile' command to generate classes.
Info: Some modules might require static view files to be cleared. To do this, run 'module:enable' with the --clear-static-content option to clear them.

$ bin/magento setup:db:status
...
Run 'setup:upgrade' to update your DB schema and data.
$ echo $?
2

$ bin/magento setup:upgrade
...
Data install/update:
Data post-updates:
Running data recurring...
...
Upgrade completed successfully.

$ bin/magento setup:db:status
...
All modules are up to date.
$ echo $?
0

$ bin/magento module:status PocketCoffee_Skeleton
PocketCoffee_Skeleton : Module is enabled

$ grep -n "PocketCoffee_Skeleton" app/etc/config.php
348:        'PocketCoffee_Skeleton' => 1,

$ mariadb magento -e "select patch_name from patch_list where patch_name like '%Skeleton%'"
PocketCoffee\\Skeleton\\Setup\\Patch\\Data\\RecordSkeletonInstall

$ mariadb magento -e "select scope,scope_id,path,value from core_config_data where path like 'pocketcoffee_skeleton%'"
default  0  pocketcoffee_skeleton/general/seeded  1

$ mariadb magento -e "select * from setup_module where module like 'Pocket%'"
(no rows)

$ curl -s http://localhost:8082/pcskeleton/index/index
Pocket Coffee beans rest at least 4 days after roasting.

# PHP syntax of every file
$ find app/code/PocketCoffee/Skeleton -name '*.php' | xargs -n1 php -l
No syntax errors detected in app/code/PocketCoffee/Skeleton/registration.php
...

# XML against the Magento schemas (the urn: catalog resolves the schema names)
$ export XML_CATALOG_FILES=/tmp/urn-catalog.xml
$ xmllint --noout --schema vendor/mage-os/framework/Module/etc/module.xsd app/code/PocketCoffee/Skeleton/etc/module.xml
app/code/PocketCoffee/Skeleton/etc/module.xml validates

# The Magento coding standard
$ vendor/bin/phpcs --standard=Magento2 --severity=1 --extensions=php,xml,json app/code/PocketCoffee/Skeleton
FILE: .../PocketCoffee/Skeleton/etc/module.xml
FOUND 0 ERRORS AND 1 WARNING AFFECTING 1 LINE
 2 | WARNING | Line exceeds 120 characters; contains 138 characters
(the same single warning for config.xml and frontend/routes.xml, no other findings)