Like was discussed in Slack chat with @ljharb and @hzoo spaces was added with no particular reason.

https://babeljs.slack.com/archives/discussion/p1481744017001806

I'm still not sure if everything here is correct (for example source maps)

packages/babel-generator/src/generators/template-literals.js

@@ -9,9 +9,7 @@ export function TemplateElement(node: Object, parent: Object) {
 
   let value = (isFirst ? "`" : "}") + node.value.raw + (isLast ? "`" : "${");
 
-  if (!isFirst) this.space();
   this.token(value);
-  if (!isLast) this.space();
 }
 
 export function TemplateLiteral(node: Object) {

packages/babel-generator/test/fixtures/harmony-edgecase/templates-indentation/expected.js

@@ -1,15 +1,15 @@
 function multilineTemplate() {
   return `I'm done reconfoobling
-${ 'the energy motron' }
-      ${ '...or whatever' }`;
+${'the energy motron'}
+      ${'...or whatever'}`;
 }
 
 {
   const foo = `spam
 and eggs!`;
 
-  const bar = `${ 4 + 2 }`;
+  const bar = `${4 + 2}`;
 
   const hello = `Hello
-${ 'world' }`;
+${'world'}`;
 }

packages/babel-generator/test/fixtures/harmony-edgecase/templates/expected.js

@@ -15,17 +15,17 @@ Is the order a rabbit?
 `;
 
 var middles = `
-Is the order ${ order }?
+Is the order ${order}?
 `;
 
 var middles = `
-Is the order ${ order }?
+Is the order ${order}?
 `;
 
 var middles = `
-1. ${ cocoa }
-2. ${ chino }
-3. ${ rize }
-4. ${ syaro }
-5. ${ chiya }
+1. ${cocoa}
+2. ${chino}
+3. ${rize}
+4. ${syaro}
+5. ${chiya}
 `;

packages/babel-generator/test/fixtures/types/TemplateLiteral-TaggedTemplateExpression-TemplateElement/expected.js

@@ -3,7 +3,7 @@ html`<b></b>`;
 `multi
   lines`;
 
-`test ${ interpolation } test`;
+`test ${interpolation} test`;
 
 `foob