Hi,
The term 'subject to tax' means that "the income must be subject to tax in the territory to qualify for relief from UK tax". This varies from country to country, however, with Israel, property income dividends, dividends, interest, royalties, other pensions / annuities and other income are all subject to tax, with some conditions being applied.
You can see the tax treaty with the UK here:
Israel: tax treaties
and the Double Taxation digest for general information here:
Digest of Double Taxation Treaties April 2018
Thank you.