How to remove the default  tags generated by modifying manage display?
It seems you are missing the  Display Suite Extras submodule (ds_extras)?
You can change the default field templates easily there.
From DS Extras doc:

Default Field Template

Default: will output the field as defined in Drupal Core.
Reset: will strip all HTML.
Minimal: adds a simple wrapper around the field.
Expert Field Template: gives full control over the
HTML, but can only be set per field.

You can override this setting per field on the &quot;Manage display&quot;
screens or when creating fields on the instance level.

admin/structure/ds/list/extras:

Once the Extras submodule activated you will have control by fields. visit the CT &quot;manage display&quot; page and the main CT page (edit). Mode &quot;Minimal&quot; or &quot;Expert&quot; seems what you need.