The rainbow icon is used to give some indication of the LGBT status of a country. A cross denotes that same-sex acts are illegal, a tick denotes that same sex marriage +/- civil unions are legal and there is pro Trans legislation and a question mark suggests that the country has some legislation that protects LGBT citizens. Click the icon and a pop up appears with information.
This information is not just important for LGBT travellers. All travellers should be aware that there are different legal systems and laws in the countries that they are visiting and it also gives a clue to wider societal tolerances or lack thereof. Further info can be found in the Travel Advice sections of each country page (from Foreign and Commonwealth Office).
We have taken information from:
State Sponsored Homophobia - A World Survey of Sexual Orientation Laws 2017
Trans Legal Mapping Report 2017
Both reports are available at http://ilga.org