Revelation 13:6

And he opened his mouth in blasphemy against God, to blaspheme his name, and his tabernacle, and them that dwell in heaven. [KJV]

And he opened the mouth of himself for blasphemy against the God, to blaspheme the name of him, and the tabernacle of him, and those in the heaven, tabernacling. [Diaglott]

And he opened his mouth in blasphemies against God, to blaspheme His name and His tabernacle, that is, those who dwell in heaven. [NASB]

and it did open its mouth for evil-speaking toward God, to speak evil of His name, and of His tabernacle, and of those who in the heaven tabernacle, [YLT]

And it opened its mouth in blasphemies against God, to blaspheme his name, and his tabernacle, even them that dwell in the heaven. [RVIC]

And he opened his mouth for blasphemy against God, to blaspheme his name, and his tent, - them, who, in heaven were tabernacling. [ROTH]

Of the above translations the one which seems to most closely capture the original is the RVIC. My only slight modification would be to indicate that 'God' in this verse should be 'the God' as it is (according to Wescott and Hort) preceded by the Greek article the ('ho' - Strongs 3588), thus indicating 'the God' as opposed to 'God' or 'a god.')

And opened his mouth for blasphemy against the God, blasphemed his name and his tabernacle - those [who] in the heaven reside. [Our translation based on the Greek and Strong's Concordance]

The understanding of this verse, for the most part, is not difficult.

And he The papal beast, i.e., the Roman empire with seven heads, the current head, at the time of this prophecy, being the papacy.
opened his mouth in blasphemy against God, It is against God that the anti-christ system speaks blasphemy by proclaiming various God dishonoring doctrines (eternal torment, trinity, etc.)
to blaspheme his name, Not only do the false doctrines blaspheme God but, in addition to that, the Pope has taken various titles which blaspheme God's name because these titles belong to God or His Son. Among these are: 'Most Divine of all Heads,' 'Holy Father of Fathers,' 'Vicar of Christ,' 'Ruler of the House of the Lord,' 'Head of all the Holy Priests of God.'
and his tabernacle, His house, the true church.
and them that dwell in heaven.

'His Tabernacle'

While the question surrounding this verse has to do primarily with the last phrase: 'them that dwell in heaven,' nevertheless there are those who think 'his tabernacle' refers to the Plan of God and not the church. Brother Russell said this refers to the church. Therefore we will make a brief examination of the use of the Lord's 'tabernacle' in the New Testament in order to see how the Lord is using it, comparing scripture with scripture. As we examine these verses let us remember that not every use of the word tabernacle refers to the Lord's tabernacle. We are confining our references only to those verses which refer to either the tabernacle of God or to a tabernacle associated with His people.

Strong's 4633 - skay-nay'
Apparently akin to G4632 and G4639; a tent or cloth hut (literally or figuratively): - habitation, tabernacle.

Act 7:44 Our fathers had the tabernacle of witness in the wilderness, as he had appointed, speaking unto Moses, that he should make it according to the fashion that he had seen.

It should be noted that 'the tabernacle of witness' clearly refers to the tabernacle in the days of Moses. The word 'witness' here is Strong's 3142. Why is this important? Because one of the three uses of the word 'tabernacle' in Revelation (15:5) makes reference to 'the tabernacle of the testimony.' The word 'testimony' in that verse is also Strong's 3142.

Act 15:16 After this I will return, and will build again the tabernacle of David, which is fallen down; and I will build again the ruins thereof, and I will set it up:

How could the tabernacle of David have reference to the plan of God? This has reference to the re-establishment of the Kingdom of God, not the typical Kingdom, as in the days of King David, but the true Kingdom. See Q790:1; R5805; R4512:3; C256

Heb 8:1,2 Now of the things which we have spoken this is the sum: We have such a high priest, who is set on the right hand of the throne of the Majesty in the heavens; [2] A minister of the sanctuary, and of the true tabernacle, which the Lord pitched, and not man.

Heb 9:2,3 For there was a tabernacle made; the first, wherein was the candlestick, and the table, and the shewbread; which is called the sanctuary. [2] And after the second veil, the tabernacle which is called the holiest of all;

Heb 13:10 We have an altar, whereof they have no right to eat which serve the tabernacle.

Of particular importance would be the other places in the book of Revelation where we see the use of the word 'tabernacle.' There are only two.

Rev 15:5 And after that I looked, and, behold, the temple of the tabernacle of the testimony in heaven was opened:

The temple of the tabernacle would seem to refer to the Most Holy. This does not seem to indicate the Divine Plan. It is from here that the 7 angels who have the plagues come out of.

Rev 21:3 And I heard a great voice out of heaven saying, Behold, the tabernacle of God is with men, and he will dwell with them, and they shall be his people, and God himself shall be with them, and be their God.

From the above it seems clear that the tabernacle of God has reference in some fashion to His people.

In this table the Strong's numbers are within [brackets]
[2532] and [2532] and
[455] to open [455] to open
[3588] the [848] he/his
[4750] mouth [4750] mouth
[846] he/his
[1519] in/for [1519] in/for
[988] blasphemy [988] blasphemy
[4314] toward / against [4314] toward / against
[3588] the
[2316] God (theos) [2316] God (theos)
[987] blasphemes [987] blasphemes
[3588] the [848] he/his
[3686] name [3686] name
[846] he/his
[2532] and [2532] and
[3588] the [848] he/his
[4633] tent / tabernacle [4633] tent / tabernacle
[846] he/his [2532] and
[3588] the [4637] camp/reside/dwell
[1722] in [1722] in
[3588] the
[3772] heaven [3772] heaven
[4637] camp/reside/dwell
Our translation based on the foregoing
And opened his mouth for blasphemy against the God, blasphemed his name and his tabernacle those in heaven reside. And opened his mouth in blasphemy against God, blasphemed his name and his tabernacle and [those that] reside in heaven.