Has anyone tried these? Does the ATtiny have a bootloader? What software is used to program the chip? Arduino compatible?
Looks a lot more convenient than programming the ATtiny via an Uno.
If you don't have experience working with AVRs at a low level then stay away from that. It doesn't provide any connection for a programmer and relies on the Micronucleus bootloader already being in place.
If you really want to experiment with ATtiny development then go with either an Adafruit Trinket or a Digistump Digispark (both of which already have Micronucleus loaded), or get an AVR programmer and (optionally) a ATtiny13/25/45/85 development board that includes a 6- or 10-pin programming header
TL;DR: It's basically a bigger digispark with a socket and different header.
Just for completeness:
It depends on the product description, recently I ordered two of your link and some of these. Those seem to be the same board as you asked for, but in your link the "Package includes" only mentions the board without MCU, which would render the question pointless.
Like Ignacio already said correctly, without proper equipment you wont get this to work with the Arduino IDE. Once you have a bootloader (e.g. micronucleus) on it (the MCU), you can use it like a digispark.
In fact the USB connection works just like on the digispark and ist not only for power.
The mounted ATtiny85 was preflashed with micronucleus v1.6 and registered as vendor=16d0, product=0753, which means you could even start with it right away, with Arduino IDE and the digistump board manager.
Personally I use these for prototyping small projects with those tinies on the go where you often don't need a programmer. Once you're done or want to do more you can always remove the bootloader and continue with a real programmer. Or you want to reflash while using the reset pin for I/O, also handy.
This board supports Attiny25/45/85 MCUs. It is possible to use bootloader with this board. It can be a low speed (1.5MBps) USB device. More info can be found in this article: https://makbit.com/web/firmware/breathing-life-into-digispark-clone-with-attiny-mcu/
I don't see than much usefulness in these boards.
So in conclusion, some minor plus sides, and some major downsides.
Just place the 8-pin DIP ATtiny in a breadboard.
The socket is important. One of the huge benefits of using these 8 pin packages is the ability to plug and pull over and over again. Sadly there are few development boards not obsessed with USB. Thankfully this one's is a power header and can be removed easily enough. The Digi/Ada offerings and their clones are not socketed. They are also simple enough to do your own boards.
You can program the x5's with the SparkFun Tiny AVR programmer, based on a design by D.A.Mellis using leads, or by transplanting the mcu. And you can do it from an Arduino, either way you are making up or sourcing a lead, as squid style flying leads are tedious.
Otherwise there is a 2k or so bootloader that can be used, which would be most useful for the 85. Without serial support from USB or FTDI this will be hard.