In your App Catalog the Title column is not editable for a custom SharePoint Framework (SPFx) web part.
In order to change your custom web parts title, simply edit the package-solution.json.
Located under config > package-solution.json.
Change this “name” to something more user friendly.
Now once the package is bundled and deployed you will see the corresponding name.
This would be a good place to rename your custom apps to match the branding of your site or to provide some way to recognize these apps were created by you.
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