What is a home return permit?
when was the deadline?
and why was there a deadline to get one?
If you'll only answer one of these questions, answer the last one.
I'm not 100% sure of the accuracy of this information since I had a look at this a few years ago and didn't bother to really update this. So guests and readers feel free to correct any omissions I may make or corrections.
Effectively they are like European Schengen passports which allow you to travel freely in China (Mainland China, both S.A.R zones) without Visas (strangely Taiwan accepts them as proof of identity too). Visas take time are costly and the visas on the day at Lo Wu are restricted to Schenzhen China. Thus if you want you can drive to Macau leaving HK travelling along past Zhuhai and down into Macau without the need for a visa or take a bus instead of being limited to the ferry.
Home return permits are still available if you want them they come at a high price for the benefits which they give you.
Pre 1997 and up to 1999 ANY ETHNIC CHINESE even if you had negligible amount of Chinese blood in you could apply for a Home return permit and they'd give you one as they were given out like candy. This was completely independent of citizen ships as it was effectively a 10 year visa which you carried around with you when you went to visit mainland China.
The brown ones were phased out in favor of smart cards which allow you to use the automated terminals at Low Wu and Lok Ma Chau. Much like HKID cards.
In 1999 they stopped this to make the PRC law more consistent and unify the laws of PRC China/SAR HK. Since many HK people have citizen ships elsewhere, my dad has UK citizenship for example. But PRC law does not recognise dual citizenship, Hong Kong isn't the PRC though.
There is a strange situation because Hong Kong isn't actually a country it is part of China but at the same time not if you get what I mean.
If you are born in HK the chance of you getting one is high, it can take a very long time to get them though 7-10 months is an oft quoted figure, but I have no direct experience of this myself. However a high chance does not mean guarenteed as people who the PRC don't like (you can probably stick TCG on this list as TCG is banned in Mainland China).
If you were born overseas and have a second citizenship (TCG has more than two) there is no way in hell you can get a home return permit other than via some massive chicanery Patrick the occasional guest writer for ATCG managed to retain both his Canadian and HK citizen ships separately. I mean Zeman who has a dump truck full of money didn't manage to get a home return permit while Patrick did.
But if you want one you need to renounce all other citizen ships really renounce before you will be even considered for one. Zeman of LKF fame for example in the video below renounced his Canadian citizenship to get a Home return permit (his money helped too no doubt).
Many people simply don't bother to get them due to the high price of citizen ship being restricted to one country, my dad won't get one (a new one) because he'll lose his UK pension and he worked 40+ years for that.
However the consequences for HK born no dual nationality types getting a home return permit are negligible and it allows them to go over to China to go drinking where the beer is cheaper amongst many things and come back to HK to work. Peter another family friend lives right on the border and he is a cheap bastard, he crosses regularly for meals as they are so much cheaper than in HK. And he can get those cheap Macau holidays too where they take you via bus to Macau so the holiday often costs 50% of a ferry holiday.