They're bootstrap themes - basically customisations to the colour, spacing, font, borders etc.
I dont use bootstrap themes like this myself directly but they can have a very useful purpose (which I intend to take advantage of)
Suppose you release an application, it doesn't matter if it's OSS, Commercial, or even hosted SaaS. It's a business web-app, so you use Bootstrap as your "UI Kit". Ok, Bootstrap has some basic default styles, and you maybe have a designer create a custom theme for your app.
But the user/customer wants to customise the appearance, perhaps it's exposed to their clients somehow, perhaps it's visible on a physical terminal in a shop.
Either way - this is where bootstrap themes (and I mean themes, like these - not so much those "Bootstrap Dashboard" which use a whole whack of extra JS libraries, markup and css) like the linked ones, or those found on https://bootswatch.com can be very effective.
If you build several applications, the effect is magnified, as the customer/user can now use multiple apps with the same custom theme, with almost no work at all from you.
I dont use bootstrap themes like this myself directly but they can have a very useful purpose (which I intend to take advantage of)
Suppose you release an application, it doesn't matter if it's OSS, Commercial, or even hosted SaaS. It's a business web-app, so you use Bootstrap as your "UI Kit". Ok, Bootstrap has some basic default styles, and you maybe have a designer create a custom theme for your app.
But the user/customer wants to customise the appearance, perhaps it's exposed to their clients somehow, perhaps it's visible on a physical terminal in a shop.
Either way - this is where bootstrap themes (and I mean themes, like these - not so much those "Bootstrap Dashboard" which use a whole whack of extra JS libraries, markup and css) like the linked ones, or those found on https://bootswatch.com can be very effective.
If you build several applications, the effect is magnified, as the customer/user can now use multiple apps with the same custom theme, with almost no work at all from you.