I'm looking for an online resource where I can enter the ticker symbol of an ETF and I can see the percentage of its dividends that is regarded as qualified dividends by the IRS. Does such resource exist?
Investopedia has a pretty extensive article on this.
Assuming the ETF is a US ETF, then the disqualifying criteria is:
Dividends That Do Not Qualify
Some dividends are automatically exempt from consideration as a qualified dividend. These include dividends paid by real estate investment trusts (REITs), master limited partnerships (MLPs), those on employee stock options, and those on tax-exempt companies. Dividends paid from money market accounts, such as deposits in savings banks, credit unions, or other financial institutions, do not qualify and should be reported as interest income.7
Special one-time dividends are also unqualified. Lastly, qualified dividends must come from shares that are not associated with hedging, such as those used for short sales, puts, and call options. The aforementioned investments and distributions are subject to the ordinary income tax rate.
Of course, there's also the holding period requirement which you need to satisfy.
So generally, US ETF dividends can be qualified dividends if the holding period requirement is satisfied, unless they fall into any of the above mentioned categories.
Because of the holding period requirement, the qualification is sometimes determined after the tax year ends, which is one of the reasons why 1099s from brokerage firms are usually late and frequently corrected (there are a couple of more common reasons, also related to dividends - other preferential treatments, reclassification to/from cap/gain/dividend distributions, etc).