@infograf768 can you forward this to the respective TT's?

uk.js right version:

window.JoomlaCalLocale = {
	today : "Сьогодні",
	weekend : [0, 6],
	wk : "тждн.",
	time : "Час:",
	days : ["Неділя", "Понеділок", "Вівторок", "Середа", "Четвер", "П'ятниця", "Субота"],
	shortDays : ["Нд.", "Пн.", "Вт.", "Ср.", "Чт.", "Пт.", "Сб."],
	months : ["Січень", "Лютий", "Березень", "Квітень", "Травень", "Червень", "Липень", "Серпень", "Вересень", "Жовтень", "Листопад", "Грудень"],
	shortMonths : ["Січ.", "Лют.", "Бер.", "Квіт.", "Трав.", "Черв.", "Лип.", "Серп.", "Вер.", "Жовт.", "Лист.", "Груд."],
	AM : "AM",
	PM :  "PM",
	am : "am",
	pm : "pm",
	dateType : "gregorian",
	minYear : 1900,
	maxYear : 2100,
	exit: "Закрити",
	save: "Зберегти",
	clear: "Очистити"
};

ru.js right version:

window.JoomlaCalLocale = {
	today : "Сьогодні",
	weekend : [0, 6],
	wk : "тждн.",
	time : "Час:",
	days : ["Неділя", "Понеділок", "Вівторок", "Середа", "Четвер", "П'ятниця", "Субота"],
	shortDays : ["Нд.", "Пн.", "Вт.", "Ср.", "Чт.", "Пт.", "Сб."],
	months : ["Січень", "Лютий", "Березень", "Квітень", "Травень", "Червень", "Липень", "Серпень", "Вересень", "Жовтень", "Листопад", "Грудень"],
	shortMonths : ["Січ.", "Лют.", "Бер.", "Квіт.", "Трав.", "Черв.", "Лип.", "Серп.", "Вер.", "Жовт.", "Лист.", "Груд."],
	AM : "AM",
	PM :  "PM",
	am : "am",
	pm : "pm",
	dateType : "gregorian",
	minYear : 1900,
	maxYear : 2100,
	exit: "Закрити",
	save: "Сохранить",
	clear: "Очистить"
};

english version wrong too. I think it is global mistake.

Mistake also in en.js?

Sorry to say, but all calendar language js files are made on the model of en.js where we have

	exit: "Close",
	save: "Clear"

The param IS "save" but the value IS "Clear" and that is what it does, i.e. clearing the field.
Saving is done by hitting the "Enter" key or next to the dropdown.

button "Clear" works fine but it is not translating in other languages.
because option "clear" is missing and his value now into option "save" but "save" not using in calendar.
and option "save" translated wrong

What the heck. You are partly right.
We must not change the value but the param indeed.
In English it is always fine, but not for other languages.
We need to change all the language locales to (for French)

clear: "Effacer"

instead of

save: "Effacer"

We do not need the option save:"whatever" at all...

will do patch now for all locales.

Thanks you for pointing to this issue.

Please test #22026

Closing as we have patch