An extension touches the ABAP back end, the Gateway (ABAP front end), and the UI layer. A teammate opens SEGW to add a DDIC append field. What did they get wrong, and which tool belongs to each layer?

When you add a property to an entity type in a redefined SEGW service, you fill in Name, Label, EDM Core Type, Max Length, and the ABAP Field Name binding. If the binding and the EDM type/length disagree, which one governs — and why does that matter?

SAP ships the full SAPUI5 project of every transactional app. Does that mean you can insert custom content anywhere in any view — and how do you know where you actually can?

A colleague claims the nine-step Fiori extension flow survives standard-app upgrades 'because everything is in its own transport.' Why is that the wrong reason, and what is the real one?

You deployed a custom app and set up LPD_CUST, the FLP catalog/tile, and a PFCG role — but the tile still 404s. Which easily-skipped step did you likely miss?

Your extended view shows the binding key {i18n>EXT_STATE} literally instead of the word 'State'. Where must the text live, and why not in the app's existing properties file?

You need a new field in an app's data at the Business Suite layer. Why use an append structure on the OData DDIC structure rather than editing that structure directly — and what's the path?