diff --git a/bookshop/server.js b/bookshop/server.js
index aa8a7484..257b1b12 100644
--- a/bookshop/server.js
+++ b/bookshop/server.js
@@ -1,9 +1,9 @@
-const cds = require ('@sap/cds')
 const {resolve} = require ('path')
 const {promisify} = require('util')
 const readFile = promisify(require('fs').readFile)
 const swaggerUi = require ('swagger-ui-express')
-const DEBUG = cds.debug('openapi')
+const cds = require ('@sap/cds')
+const trace = cds.debug('openapi')
 
 let app, host, docCache={}
 
@@ -16,18 +16,18 @@ cds
       req.swaggerDoc = await toOpenApiDoc(service, host, docCache)
       next()
     }, swaggerUi.serve, swaggerUi.setup())
-    addLink(service, apiPath)
+    addLinkToIndexHtml(service, apiPath)
   })
   .on ('listening', ({server})=> { host = 'localhost:'+server.address().port })
 
 async function toOpenApiDoc(service, host, cache) {
   if (!cache[service.name]) {
     const spec = await openApiFromFile(service, host)
-    if (spec) {
+    if (spec) {  // pre-compiled spec file available?
       cache[service.name] = spec
     }
     else if (cds.compile.to.openapi) {  // on-the-fly exporter available?
-      DEBUG && DEBUG ('Compiling Open API spec for', service.name)
+      trace && trace ('Compiling Open API spec for', service.name)
       cache[service.name] = cds.compile.to.openapi (service.model, {
         service: service.name,
         'openapi:url': service.path,
@@ -42,17 +42,17 @@ async function openApiFromFile(service) {
   const fileName = resolve(`srv/${service.name}.openapi3.json`)
   const file = await readFile(fileName).catch(()=>{/*no such file*/})
   if (file) {
-    DEBUG && DEBUG ('Using Open API spec from file', fileName)
+    trace && trace ('Using Open API spec from file', fileName)
     return JSON.parse(file)
   }
 }
 
-function addLink(service, apiPath) {
-  const link = (entity) => {
-    if (entity)  return // don't want to provide link on entity level
+function addLinkToIndexHtml(service, apiPath) {
+  const provider = (entity) => {
+    if (entity)  return // avoid link on entity level, looks too messy
     return { href:apiPath, name:'Swagger UI', title:'Show in Swagger UI' }
   }
-  service.$linkProviders ? service.$linkProviders.push(link) : service.$linkProviders = [link]
+  service.$linkProviders ? service.$linkProviders.push(provider) : service.$linkProviders = [provider]
 }
 
 module.exports = cds.server