public Builder clearNfVersion() {
      nfVersion_ = getDefaultInstance().getNfVersion();
      bitField0_ = (bitField0_ & ~0x00000004);
      onChanged();
      return this;
    }
<pre>
Output only. NF version.
</pre>

<code>string nf_version = 3 [(.google.api.field_behavior) = OUTPUT_ONLY];</code>

@return This builder for chaining.
java-telcoautomation/proto-google-cloud-telcoautomation-v1/src/main/java/com/google/cloud/telcoautomation/v1/SiteVersion.java