The RoC releasing its claim on the rest of China would be a de-facto declaration of independence as well since it wound cease to be the rump state of the country founded in 1912 and become something else.
do they still claim this? is this official? or old KMT rhetoric
It’s written into their Constitution. Taiwan doesn’t care for China at all. Just wants to be left alone to live and continue to prosper.
The constitution says so. However, it was amended in the early 90ties to acknowledge that the scope of the ROC government is presently limited to Taiwan and the outlying islands.