As we all know that pronunciation is a very important criteria in the speaking part of your IELTS test. Here is the marking guide for pronunciation in band 6, 7, and 8
Accent, everybody has their own accent when they speak English, and accent is not the marking guide, however, it would definitely affect your score.
NOTE: L1 (first language) accent is not a barrier to you being understood when you're speaking English, hence the part "having minimal effect on intelligibility". Your L1 accent may be noticeable, but its effect is "minimal". It probably means that you're pretty close to sounding like a native speaker, or at least well on the way to it.