The origin may concern a warning, but it is typically used to specify a condition or a restriction attached to an offer. It will follow a statement setting out, or describing, the proposal, ‘with the caveat that . . ‘.
In effect, it is used to mean ‘on condition that . . ‘
It is used in formal writing and, occasionally, speaking.
‘The manager said that all applicants would be interviewed, with the caveat that they had agreed to submit documentary evidence of having fulfilled the requirements.’
‘He was offered the job, with the caveat that he would take a course of study to learn English.’
‘I agreed to let her go home early today, with the caveat that she would complete any unfinished work when she returns.’